Method of fabricating a semiconductor device

ABSTRACT

A conductive mounting board provided in a package has recessed portion and a projecting portion, and an insulating mounting board is disposed on the recessed portion. The insulating mounting board is disposed on the recessed portion. The insulating mounting board has an insulating board on the surface of which a wiring portion is disposed. A semiconductor laser, constituted by stacked semiconductor layers each being made from a compound semiconductor composed of a group III based nitride, is disposed on the insulating mounting board and the conductive mounting board. An n-side electrode of the semiconductor laser is in contact with the insulating mounting board and a p-side electrode thereof is in contact with the conductive mounting board.

RELATED APPLICATION DATA

This application is a divisional of U.S. application Ser. No. 09/385,955filed Aug. 30, 1999. The present and foregoing applications claimpriority to Japanese applications Nos. P10-251602 filed Sep. 4, 1998,and P10-334735 filed Nov. 25, 1998. All of the foregoing applicationsare incorporated herein by reference to the extent permitted by law.

The present invention relates to a semiconductor device including asemiconductor element disposed on a mounting board and a package havingthe mounting board, and fabrication methods thereof.

At present, semiconductor light emitting devices are being used invarious industrial fields. Such a semiconductor light emitting device isgenerally configured such that a semiconductor light emitting element iscontained in a package. The package is adapted to achieve simplehandling and protection of the light emitting element, and toefficiently radiate heat generated in the light emitting element uponoperation of the light emitting device. In recent years, there have beenstrong demands to develop a high output semiconductor light emittingdevice, and to develop a semiconductor light emitting device foremission of green light using a compound semiconductor composed of acompound containing a group II element and a group VI element or asemiconductor light emitting device for emission of blue color using acompound semiconductor composed of a nitride containing nitrogen and agroup III element. To meet such demands, a power supplied to the lightemitting element tends to be increased, with a result that the amount ofheat generation from the light emitting element becomes far larger. Fromthis viewpoint, it is expected to enhance the heat radiation effect bymeans of the package for radiating the heat generation from the lightemitting element.

FIG. 1 shows a related art semiconductor light emitting device having aconfiguration in which a semiconductor light emitting element 2220 isdisposed via a sub-mount 2219 made from an insulator on a conductivemounting board 2213 made from a metal (see Japanese Patent Laid-open No.Hei8-321655). Such a semiconductor light emitting device is advantageousin that electrical connection to the semiconductor light emittingelement can be easily performed by providing suitable wires on thesub-mount 2219. Specifically, the technique disclosed in this documentis particularly effective for a semiconductor light emitting device inwhich a semiconductor light emitting element using a compoundsemiconductor composed of a nitride containing a group III element isformed on an insulating substrate and a p-side electrode and an n-sideelectrode are both provided on the side, opposed to the insulatingsubstrate, of the light emitting element. Since the sub-mount 2219 isconnected to the semiconductor light emitting element 2110, the p-sideelectrode and the n-side electrode may be connected to pins by way ofthe sub-mount 2219, to thereby make the area required for wire bondinglarge on the sub-mount 2219. A current can be injected into thesemiconductor light emitting device from the p-side electrode and then-side electrode connected to the two pins shown in FIG. 1 via thesub-mount 2219.

FIG. 2 shows an other related art method for electrical connection of asemiconductor light emitting device including a semiconductor lightemitting element using a compound semiconductor composed of a nitridecontaining a group III element. Referring to FIG. 2, a p-side electrodeof the semiconductor light emitting device is connected to a left pinand an n-side electrode thereof is connected to a third pin (not shown)via a sub-mount 2129 and a conductive mounting board 2121. With thiselectrical connection, a current can be injected into the semiconductorlight emitting device. Further, a photodetector (not shown) formonitoring optical output of the semiconductor light emitting device isdisposed on the conductive mounting board 2121, wherein a firstelectrode of the photodetector is connected, together with thesemiconductor light emitting device, to the common third pin not shown,and a second electrode of the photodetector is connected to a right pin.With this configuration, the optical output of the semiconductor lightemitting device can be monitored by the photodetector.

The above-described technique, however, has a problem. Since aninsulator is lower in both thermal conductivity and electricalconductivity than a metal, the p-side electrode and the n-side electrodeprovided on the same side are prevented from being short-circuited byusing the insulating sub-mount 2219 or 2129, however, the heat radiationcharacteristic of the device is reduced. As a result, the temperature ofthe semiconductor light emitting element is raised, thereby degradingthe stable operation and reliability of the device for a long-period oftime.

A known semiconductor device of this type is configured such that awiring portion is formed on a flat surface of a conductive board via athin insulating film, and a p-side electrode of a semiconductor lightemitting element is connected to the conductive board and an n-sideelectrode of the element is connected to the wiring portion. Such asemiconductor device, however, is disadvantageous in that since thewiring portion is formed on the conductive board via the thin insulatingfilm, it is impossible to ensure the sufficient insulation of the wiringportion from the conductive board.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a semiconductor deviceand a package, which are capable of ensuring a high heat radiationeffect while preventing short-circuit between electrodes, andfabrication methods thereof.

To achieve the above object, according to a first aspect of the presentinvention, there is provided a semiconductor device including aconductive mounting board having a recessed portion and a projectingportion disposed on said conductive mounting board; an insulatingmounting board disposed on said recessed portion of said conductivemounting board; and a semiconductor element having one portion disposedon said conductive mounting board and the other portion disposed on saidinsulating mounting board. With this configuration, it is possible toensure electrical insulation of the semiconductor element and radiateheat generated in the semiconductor element via the conductive mountingboard, and hence to suppress temperature rise of the semiconductorelement and thereby ensure a stable operational state of the device fora long-period of time. As a result, it is possible to improve thereliability of the semiconductor device.

In this semiconductor device, preferably, the first electrode isdisposed on a portion, on the side where the active layer is provided,of the first conduction type semiconductor layer and the secondelectrode is disposed on a portion, on the side opposed to the activelayer, of the second conduction type semiconductor layer; and also thefirst electrode is disposed on the insulating mounting board and thesecond electrode is disposed on the conductive mounting board. With thisconfiguration, it is possible to shorten the distance between the activelayer and the conductive mounting board and hence to positively radiateheat generated in the active layer via the conductive mounting board. Asa result, it is possible to suppress temperature rise of thesemiconductor element and to prevent short-circuit between the firstelectrode and the second electrode of the semiconductor element.

In the semiconductor device, preferably, the semiconductor element isconfigured such that a plurality of the light emitting portions areformed on the same substrate. With this configuration, it is possible toradiate heat generated in each active layer via the conductive mountingboard, and hence to suppress thermal interference between the lightemitting portions. As a result, it is possible to suppress an increasein threshold current and a reduction in luminous efficiency in eachlight emitting portion, and hence to ensure a high quality of the devicefor a long-period of time.

In the semiconductor device, a separating portion is preferably providedon the conductive mounting board at a position between the recessedportion and the projecting portion. With this configuration, it ispossible to more effectively ensure the insulation of the semiconductorelement.

In the semiconductor device, a position fixing portion is preferablyprovided on the conductive mounting board in such a manner as to providethe recessed portion between the projecting portion and the positionfixing portion. With this configuration, it is possible to easily andaccurately dispose the insulating mounting board on the conductivemounting board.

In the semiconductor device, the insulating mounting board may be formedon the recessed portion of the conductive mounting board by deposition.With this configuration, it is possible to easily and accurately disposethe insulating mounting board at a low cost.

According to a second aspect of the present invention, there is provideda package including a conductive mounting board having on its onesurface a recessed portion and a projecting portion; and an insulatingmounting board disposed on the recessed portion of the conductivemounting board. With this configuration, it is possible to ensureelectrical insulation of the semiconductor element by the presence ofthe insulating mounting board and to ensure the heat radiationcharacteristic by the presence of the conductive mounting board.

In this package, preferably, the conductive mounting board has therecessed portion on which the insulating mounting board is to bedisposed and the projecting portion on which the semiconductor elementis to be disposed. With this configuration, it is possible to ensureelectrical insulation of the semiconductor element by the insulatingmounting board disposed on the recessed portion and to positivelyradiate heat generated in the semiconductor element via the conductivemounting board.

According to a third aspect of the present invention, there is provideda method of fabricating a semiconductor device, including the steps of:forming a conductive mounting board having on its one surface a recessedportion and a projecting portion; forming an insulating mounting boarddisposed on the recessed portion of the conductive mounting board;forming a semiconductor element; and disposing one portion of thesemiconductor element on the conductive mounting board and alsodisposing the other portion of the semiconductor element on theinsulating mounting board. With this configuration, it is possible toeasily fabricate the semiconductor device, and hence to easily realizethe semiconductor device of the present invention.

According to a fourth aspect of the present invention, there is provideda method of fabricating a package including the steps of: forming aconductive mounting board having on its one surface a recessed portionand a projecting portion; and forming an insulating mounting boarddisposed on the recessed portion of the conductive mounting board. Withthis configuration, it is possible to easily fabricate the package, andhence to easily realize the package of the present invention.

The method of fabricating the package, preferably, includes the step of:forming a conductive mounting board having on its one surface a recessedportion on which an insulating mounting board is to be disposed and aprojecting portion on which a semiconductor element is to be disposed.With this configuration, it is possible to easily fabricate the package,and hence to easily realize the package of the present invention.

According to a fifth aspect of the present invention, there is provideda semiconductor device including: a semiconductor element having aplurality of stacked semiconductor layers and also having a firstelectrode and a second electrode provided on the same side in thestacking direction; and a conductive mounting board for supporting thesemiconductor element in a state in which one of the first electrode andthe second electrode of the semiconductor element is fixed to theconductive mounting board. With this configuration, it is possible toprevent short-circuit between the first electrode and the secondelectrode and to positively radiate heat generated in the semiconductorelement via the conductive mounting board. This makes it possible tosuppress temperature rise of the semiconductor element and to keep astable operational state of the device for a long-period of time. As aresult, it is possible to improve the reliability of the semiconductordevice.

In this semiconductor device, preferably, the first electrode isprovided on a portion, on the second conduction type semiconductor layerside, of the first conduction type semiconductor layer; and the secondelectrode is provided on a portion, on the side opposed to the firstconduction type, of the second conduction type semiconductor layer andis also fixed to the conductive mounting board. With this configuration,it is possible to shorten the distance between the active layer and theconductive mounting board, and hence to more effectively radiate heatgenerated in the semiconductor element via the conductive mountingboard.

In the semiconductor device, preferably, a side surface of theconductive mounting board is tilted, from the mounting surface side tothe opposed side, toward one of the first electrode and the secondelectrode. With this configuration, it is possible to broaden a spacenear the other electrode, and hence to facilitate the electricalconnection of the other electrode to a power source.

In the semiconductor device, preferably, the conductive mounting boardis located to be shifted rightwardly from the center of the supportingsurface when the mounting surface of the conductive mounting board isdirected upwardly. With this configuration, it is possible to easily fixone of the first electrode and the second electrode to the conductivemounting board, and to easily connect the other electrode to a powersource in accordance with Japanese Industrial Standards.

In the semiconductor device, preferably, the support has the fixinggroove for fixing the conductive mounting board with the mountingsurface directed downwardly. With this configuration, it is possible tofacilitate the electrical connection of the other of the first electrodeand the second electrode to a power source.

According to a sixth aspect of the present invention, there is provideda package including: a conductive mounting board having a mountingsurface on which a semiconductor element is to be disposed; and asupport, having a supporting surface perpendicular to the mountingsurface, for supporting the conductive mounting board by the supportingsurface; wherein the conductive mounting board is located in such amanner as to be shifted rightwardly or leftwardly from the center of thesupporting surface when the mounting surface is directed upwardly; andthe conductive mounting board has a side surface at an end, near thecenter of the support, in the direction parallel to the mounting surfaceand the supporting surface, the side surface being tilted, from themounting surface side to the opposed side, toward the opposed end of themounting surface. With this configuration, in the case of mounting thesemiconductor element having the first electrode and the secondelectrode on the same side, one of the first electrode and the secondelectrode can be easily fixed to the conductive mounting board. Thismakes it possible to prevent short-circuit of the semiconductor elementand to positively radiate heat generated in the semiconductor elementvia the conductive mounting board. Further, it is possible to broaden aspace near the other electrode, and hence to facilitate the electricalconnection of the other electrode to a power source.

According to a seventh aspect of the present invention, there isprovided a method of fabricating a semiconductor device, including thesteps of: stacking a plurality of semiconductor layers and providing afirst electrode and a second electrode on the same side in the stackingdirection, to form a semiconductor element; and disposing thesemiconductor element on the conductor mounting board while fixing oneof the first electrode and the second electrode on the conductivemounting board. With this configuration, it is possible to easilyfabricate the semiconductor device of the present invention, and henceto easily realize the semiconductor device of the present invention.

In the above fabrication method, preferably, the semiconductor elementis located on the lower side and the conductive mounting board islocated on the upper side and in such a state the other electrode isconnected to a pin by means of the wire. With this configuration, it ispossible to facilitate electrical connection of the wire, and hencefacilitate the electrical connection of the other electrode to a powersource.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a configuration of a related artsemiconductor device;

FIG. 2 is a perspective view showing a configuration of another relatedart semiconductor light emitting device.

FIG. 3 is a partially exploded perspective view showing a configurationof a semiconductor light emitting device according to a first embodimentof the present invention;

FIG. 4 is a perspective view of a conductive mounting board of thesemiconductor light emitting device shown in FIG. 3.

FIG. 5 is a perspective view of an insulating mounting board of thesemiconductor light emitting device shown in FIG. 3;

FIG. 6 is a partial sectional view of a semiconductor laser of thesemiconductor light emitting device shown in FIG. 3;

FIG. 7 is an exploded perspective view of a portion of a semiconductorlight emitting device according to a second embodiment of the presentinvention;

FIG. 8 is an exploded perspective view of a portion of a semiconductorlight emitting device according to a third embodiment of the presentinvention;

FIG. 9 is an exploded perspective view of a portion of a semiconductorlight emitting device according to a fourth embodiment of the presentinvention;

FIG. 10 is a perspective view showing one step of fabricating thesemiconductor light emitting device shown in FIG. 9;

FIG. 11 is a perspective view showing a fabrication step subsequent tothat shown in FIG. 10;

FIG. 12 is a perspective view showing a fabrication step subsequent tothat shown in FIG. 11;

FIG. 13 is a partially exploded perspective view showing the entireconfiguration of a semiconductor light emitting device according to afifth embodiment of the present invention;

FIG. 14 is a partial sectional view showing a semiconductor laser of thesemiconductor light emitting device shown in FIG. 13;

FIG. 15 is an exploded perspective view of a portion of a semiconductorlight emitting device according to a sixth embodiment of the presentinvention;

FIG. 16 is a perspective view showing a variation of the semiconductordevice of the present invention;

FIG. 17 is a perspective view showing another variation of thesemiconductor device of the present invention;

FIG. 18 is a partially exploded perspective view showing a configurationof a semiconductor light emitting device according to one embodiment ofthe present invention;

FIG. 19 is a partial sectional view of a semiconductor laser of thesemiconductor light emitting device shown in FIG. 18;

FIG. 20 is a partial exploded perspective view of a portion of a packageof the semiconductor light emitting device shown in FIG. 18;

FIG. 21 is a front view illustrating the positional relationship betweena conductive mounting board and a semiconductor laser;

FIG. 22 is a perspective view showing one step of fabricating thesemiconductor light emitting device shown in FIG. 18.

FIG. 23 is a perspective view showing a fabricating step subsequent tothat shown in FIG. 22;

FIG. 24 is a perspective view showing a fabricating step subsequent tothat shown in FIG. 23;

FIG. 25 is a front view showing a configuration of a comparative exampleof the semiconductor device shown in FIG. 18.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings. It should be noted that in thefollowing embodiments, a package combined with a semiconductor device ofthe present invention will be described simultaneously with descriptionof the semiconductor device.

(First Embodiment)

FIG. 3 shows the entire configuration of a semiconductor light emittingdevice as a semiconductor device and a package 10 according to a firstembodiment of the present invention. The semiconductor light emittingdevice includes a semiconductor laser 20 as a semiconductor element inthe package 10. The package 10 has a disk shaped support 11 and ahollowed cylinder shaped cover body 12. One end side of the cover body12 is opened and the other end side thereof is closed. The end portionof the cover body 12 on the open side is in contact with one surface ofthe support 11. The end portion of the cover body 12 on the closed sideis provided with an extraction window 12 a for extracting a laser beam,emitted from the semiconductor laser 20 contained in the package 10, outof the package 10. The cover body 12 is made from a metal such as acopper (Cu) or iron (Fe) based metal, and the extraction window 12 a ismade from a material allowing transmission of a laser beam emitted fromthe semiconductor laser 20, for example, glass or plastic.

In-side the cover body 12, a conductive mounting board 13 on which thesemiconductor laser 20 is to be mounted is formed over one surface ofthe support 11. The conductive mounting board 13 is adapted toelectrically connect the semiconductor laser 20 to a power source (notshown) and to radiate heat generated in the semiconductor laser 20. Theconductive mounting board 13 and the support 11 are integrally cast froma metal such as a copper or iron based metal, on the surfaces of which asolder film made from a solder material and having a thickness of 5 μmis formed. Specific examples of the solder materials may include tin(Sn), lead (Pb), a tin-lead alloy, a gold (Au)-tin alloy, an indium(In)-tin alloy, and an indium-lead.

As enlargedly shown in FIG. 4, the conductive mounting board 13 has, onthe surface on which the semiconductor laser 20 is to be mounted, arecessed portion 13 a and a projecting portion 13 b. These recessedportion 13 a and the projecting portion 13 b are parallel to the surfaceof the support 11. The size of each of the recessed portion 13 a and theprojecting portion 13 b is set such that the width in the directionparallel to the surface of the support 11 is 0.8 mm and the depth in thedirection perpendicular to the surface of the support 11 is 1 mm. Thedifference in height between the mounting surfaces of the recessedportion 13 a and the projecting portion 13 b is set at 300 μm. Inaddition, the thickness of the conductive mounting board 13 in thedirection perpendicular to the mounting surface of the conductivemounting board 13 may be suitably determined depending on the size ofthe cover body 12, however, it is preferred to make it as large aspossible in order to increase the heat radiation effect.

An insulating mounting board 14 is mounted on the recessed portion 13 aof the conductive mounting board 13. As enlargedly shown in FIG. 5, theinsulating mounting board 14 has an insulating board 14 a made from aninsulating material such as aluminum nitride (AlN), boron nitride (BN),or silicon carbide (SiC) An adhesive layer 14 b is provided on thesurface, on the conductive mounting board 13 side, of the insulatingboard 14 a, and is adapted to fix the insulating mounting board 14 tothe conductive mounting board 13. The adhesive layer 14 b is formed bystacking a titanium (Ti) layer having a thickness of 100 nm, a platinum(Pt) layer having a thickness of 200 nm, and a gold (Au) layer having athickness of 500 nm on the insulating board 14 a in this order. A wiringportion 14 c is formed on the surface, opposed to the conductivemounting board 13, of the insulating board 14 a. The wiring portion 14 cis formed by stacking a titanium layer having a thickness of 100 nm, aplatinum layer having a thickness of 200 nm, and a gold layer having athickness of 500 nm on the insulating board 14 a in this order.

A solder adhesive layer 14 d made from a solder material is provided ona portion of the surface, opposed to the insulating board layer 14 a, ofthe wiring portion 14 c, which solder adhesive layer 14 d is adapted tobe adhesively bonded to the semiconductor laser 20. The thickness of thesolder adhesive layer 14 d is preferably set at a value of 4 μm or morefor ensuring a sufficient adhesive strength of the solder adhesive layer14 d. The solder material for forming the solder adhesive layer 14 d maybe the same as that for forming the solder film of the conductivemounting board 13, however, the solder material is preferably selectedto have a melting point lower than that of the solder material forforming the solder film of the conductive mounting board 13. The reasonfor this is that, as will be later apparent in description of thefabrication method, in the case of adhesively bonding the conductivemounting board 13, the insulating mounting board 14, and thesemiconductor laser 20 to each other, the insulating mounting board 14is less in thermal conduction than the conductive mounting board 13. Thesoldering temperatures of the above solder materials become lower in theorder of In—Sn alloy (for example, 52 wt % In and 48 wt % Sn), In—Pballoy (for example, 75 wt % In and 25 wt % Pb), Sn—Pb alloy (forexample, 50 wt % Sn and 50 wt % Pb), Sn, Au—Sn alloy (for example, 80 wt% Au and 20 wt % Sn), and Pb. For example, if the solder film on thesurface of the conductive mounting board 13 is made from Sn, the solderadhesive layer 14 d of the insulating mounting board 14 is preferablymade from a Sn—Pb alloy.

The size of the insulating mounting board 14 is set such that the widthin the direction parallel to the surface of the support 11 is 0.8 mmeach and the depth in the direction perpendicular to the surface of thesupport 11 is 1 mm. The thickness of the insulating mounting board 14 inthe direction perpendicular to the mounting surface of the insulatingmounting board 14 is preferably set to be equal to or more than thedifference in height between the mounting surfaces of the recessedportion 13 a and the projecting portion 13 b of the conductive mountingboard 13. Here, since the difference in height between the mountingsurfaces of the recessed portion 13 a and the projecting portion 13 b isset at 300 μm, the thickness of the insulating mounting board 14 ispreferably set at a value of 300 μm or more. For the purpose of ensuringthe insulation of the insulating mounting board 14 against theconductive mounting board 13, the thickness of the insulating mountingboard 14 is preferably set at a value of 500 μm or more.

As shown in FIG. 3, the support 11 is provided with a pair of pins 15and 16 extending from inside to outside of the cover body 12. Each ofthe pins 15 and 16 is made from a metal such as a copper or iron basedmetal and the surface thereof is coated with a thin film made from gold.Insulating rings 15 a and 16 a made from glass are inserted between thesupport 11 and the pins 15 and 16, respectively, for electricallyinsulating the support 11 from the pins 15 and 16. That is to say, theconductive mounting board 13 is electrically insulated from the pins 15and 16. One end of a wire 17 made from gold having a thickness of 20 μmis connected to the pin 15, and the other end of the wire 17 isconnected to the wiring portion 14 c of the insulating mounting board 14for electrically connecting the pin 15 to the wiring portion 14 c. Thesupport 11 is also provided with a pin 18 which is electricallyconnected to both the support 11 and the conductive mounting board 13.

As shown in FIG. 6, the semiconductor laser 20 is formed by sequentiallystacking a buffer layer 22 a, a backing layer 22 b, a mask layer 23, acoating growth layer 24, an n-type semiconductor layer 25 as a firstconduction type semiconductor layer, an active layer 26, and a p-typesemiconductor layer 27 as a second conduction type semiconductor layeron one surface of a pair of opposed surfaces of a substrate 21 in thisorder. The substrate 21 is formed of a sapphire having a thickness inthe stacking direction (hereinafter, referred to simply as “thickness”)of 300 μm, and the buffer layer 22 a is formed on the C-face of thesubstrate 21.

The buffer layer 22 a, which has a thickness of 30 nm, is made from anundoped GaN. The backing layer 22 b, which has a thickness of 2 μm, ismade from a crystal of undoped GaN. The mask layer 23, which has athickness of 0.1 μm, is made from silicon nitride (SiO₂). The mask layer23 has a plurality of stripe-shaped openings 23 a extending in thedirection perpendicular to the paper plane in FIG. 6, and a plurality ofstripe shaped mask portions 23 b each formed between adjacent two of theopenings 23 a. The coating growth layer 24 grows laterally on the masklayer 23, to thereby cutoff penetration of dislocations from the backinglayer 22 b. The coating growth layer 24, which has a thickness of 10 μm,is made from undoped GaN.

The n-type semiconductor layer 25 is formed by stacking an n-sidecontact layer 25 a, an n-type clad layer 25 b, and a first guide layer25 c on the coating growth layer 24 in this order. The n-side contactlayer 25 a, which has a thickness of 3 μm, is made from n-type GaN dopedwith an n-type impurity such as silicon (Si). The n-type clad layer 25b, which has a thickness of 1 μm, is made from a mixed crystal, n-typeAl_(0.1)Ga_(0.9)N doped with an n-type impurity such as silicon. Thefirst guide layer 25 c, which has a thickness of 0.1 μm, is made fromn-type GaN doped with an n-type impurity such as silicon.

The active layer 26 is made from a mixed crystal, undoped InGaN, and hasa multiple quantum well structure including a well layer having athickness of 3 nm and made from a mixed crystal, In_(0.15)Ga_(0.85)N,and a barrier layer having a thickness of 4 nm and made from a mixedcrystal, In_(0.02)Ga_(0.98)N. The active layer 26 functions as a lightemitting layer. For example, upon laser oscillation, the emissionwavelength is set at about 405 nm.

The p-type semiconductor layer 27 is formed by stacking a deteriorationpreventive layer 27 a, a second guide layer 27 b, a p-type clad layer 27c, and a p-side contact layer 27 d on the active layer 26 in this order.The deterioration preventive layer 27 a, which has a thickness of 20 nm,is made from a mixed crystal, p-type Al_(0.2)Ga_(0.8)N doped with ap-type impurity such as magnesium (Mg). The second guide layer 27 b,which has a thickness of 0.1 μm, is made from p-type GaN doped with ap-type impurity such as magnesium. The p-type clad layer 27 c, which hasa thickness of 0.8 μm, is made from a mixed crystal, p-typeAl_(0.1)Ga_(0.9)N doped with a p-type impurity such as magnesium. Thep-side contact layer 27 d, which has a thickness of 0.5 μm, is made froma mixed crystal, p-type GaN doped with an impurity such as magnesium.

An n-side electrode 28 a as a first electrode is provided on thesurface, on the active layer 26 side in the stacking direction, of then-side contact layer 25 a. The n-side electrode 28 a is formed bystacking a titanium layer, an aluminum (Al) layer, and a gold layer onthe n-side contact layer 25 a in this order and alloying these metals byheating, to be thus electrically connected to the n-side contact layer25 a. A p-side electrode 28 b as a second electrode is provided on thesurface, opposed to the active layer 26 in the stacking direction, ofthe p-side contact layer 27 d. The p-side electrode 28 b is formed bystacking a nickel (Ni) layer and a gold layer on the p-side contactlayer 27 d in this order and alloying these metals by heating, to bethus electrically connected to the p-side contact layer 27 d. The p-sideelectrode 28 b is formed into a stripe shape extending in the directionperpendicular to the paper plane in FIG. 6 for current constriction, anda region of the active layer 26 corresponding to the p-side electrode 28b becomes a light emission region.

The semiconductor laser 20 has a pair of reflector films 29 (only one isshown in FIG. 6) at both ends of the p-side electrode 28 b in the lengthdirection. Each reflector film 29 is formed by alternately stackingsilicon nitride films and zirconium oxide (ZrO) films. The reflectanceof one reflector film 29 is set at a low value and the reflectance ofthe other reflector film (not shown) is set at a high value, so thatlight generated from the active layer 26 is reciprocated between thepair of reflector films 29 to be amplified, and is emitted from onereflector film 29 as a laser beam. That is to say, the length directionof the p-side electrode 28 b becomes the resonator orientation.

The semiconductor laser 20 is, as shown in FIG. 3, disposed in thepackage 10 in such a manner that the n-side electrode 28 a is in contactwith the solder adhesive layer 14 d of the insulating mounting board 14and the p-side electrode 28 b is in contact with the projecting portion13 b of the conductive mounting board 13. To be more specific, then-side electrode 28 a is connected to the power source (not shown) bymeans of the pin 15 via the wiring portion 14 c of the insulatingmounting board 14 and the wire 17, and the p-side electrode 28 b iselectrically connected to the power source (not shown) by means of thepin 18 via the conductive mounting board 13. The reason why the p-sideelectrode 28 b is in contact with the conductive mounting board 13 isthat the active layer 26 acting as a main heat generation source isdisposed between the p-side electrode 28 b and the substrate 21. That isto say, it is possible to obtain a high heat radiation effect byshortening the distance between the active layer 26 and the conductivemounting board 13 having a high heat radiation characteristic.

The semiconductor device and the package 10 having the aboveconfigurations are fabricated in accordance with the followingprocedure:

First, a semiconductor laser 20 is formed as follows: A substrate 21made from a sapphire having a plurality of semiconductor laser formationregions is prepared. A buffer layer 22 a made from undoped GaN and abacking layer 22 b made from undoped GaN are allowed to sequentiallygrow on one surface (C-face) of the substrate 21 by MOCVD (Metal OrganicChemical Vapor Deposition). A mask layer 23 having a plurality of stripeshaped mask portions 23 b made from silicon dioxide is selectivelyformed on the backing layer 22 b by CVD (Chemical Vapor Deposition). Acoating growth layer 24 made from undoped GaN is allowed to laterallygrow on the mask layer 23 by MOCVD.

Then, an n-side contact layer 25 a made from n-type GaN, an n-type cladlayer 25 b made from n-type Al_(0.1)Ga_(0.9)N (mixed crystal), a firstguide layer 25 c made from n-type GaN, an active layer 26 made fromundoped GaInN (mixed crystal), a deterioration preventive layer 27 amade from p-type Al_(0.2)Ga_(0.8)N (mixed crystal), a second guide layer27 b made from p-type GaN, a p-type clad layer 27 c made from p-typeAl_(0.1)Ga_(0.9)N (mixed crystal), and a p-side contact layer 27 d madefrom p-type GaN are all owed to sequentially to grow on the coatinggrowth layer 24 by MOCVD.

After growing the layers in the order from the n-side contact layer 25 ato the p-side contact layers 27 d, the p-side contact layer 27 d, thep-type clad layer 27 c, the second guide layer 27 b, the deteriorationpreventive layer 27 a, the active layer 26, the first guide layer 25 c,and the n-type clad layer 25 b are selectively removed in sequencecorrespondingly to a formation position of an n-side electrode 12 bylithography, to expose the n-side contact layer 25 a. An n-sideelectrode 28 b is then selectively formed on the n-side contact layer 25a. After formaing of the n-side electrode 28 a, a p-side electrode 28 bis selectively formed on the p-side contact layer 27 d. The n-sideelectrode 28 a and the p-side electrode 28 b are then each alloyed byheating.

After forming the n-side electrode 28 a and the p-side electrode 28 b,the substrate 21 is divided, in the direction perpendicular to thelength direction of the p-side electrode 28 b, into parts each having aspecific length corresponding to that of each semiconductor laserformation region. A pair of reflector films 29 are formed on a pair ofside surfaces of the divided part by, for example, an electron beamevaporation process. Then, the substrate 21 is divided, in the directionparallel to the length direction of the p-side electrode 28 b, intoparts having a specific width corresponding to that of eachsemiconductor laser formation region, to form a semiconductor laser 20.

After that, a support 11 and a conductive mounting board 13 having arecessed portion 13 a and a projecting portion 13 b are integrally cast,and a solder film is vapor-deposited on the surfaces of the support 11and the conductive mounting board 13. Pins 15, 16 and 18 separatelyformed are mounted to the support 11. Then, an insulating board 14 a isseparately formed, and an adhesive layer 14 b is vapor-deposited on onesurface of the insulating board 14 a and a wiring portion 14 c and asolder adhesive layer 14 d are sequentially vapor-deposited on the othersurface of the insulating board 14 a, to form an insulating mountingboard 14. After forming the insulating mounting board 14, the conductivemounting board 13 integrated with the support 11 is put in a heatingapparatus (not shown), and the insulating mounting board 14 is mountedon a recessed portion 13 a of the conductive mounting board 13, and thep-side electrode 28 b of the semiconductor laser 20 is brought intocontact with the projecting portion 13 b of the conductive mountingboard 13 and the n-side electrode 28 a of the semiconductor laser 20 isbrought into contact with the solder adhesive layer 14 d of theinsulating mounting board 14.

The conductive mounting board 13 is heated for 5 to 20 seconds up to atemperature ranging from 240 to 300° C. and held at the temperature for10 to 60 seconds by the heating apparatus (not shown) With thisheat-treatment, the solder film of the conductive mounting board 13 ismelted to adhesively bond the conductive mounting board 13 to theinsulating mounting board 14 and also to adhesively bond the conductivemounting board 13 to the p-side electrode 28 b of the semiconductorlaser 20, and simultaneously the solder adhesive layer 14 d of theinsulating mounting board 14 is melted to adhesively bond the insulatingmounting board 14 to the n-side electrode 28 a of the semiconductorlaser 20.

In this case, by setting the melting point of a solder material of thesolder adhesive layer 14 d of the insulating mounting board 14 to belower than that of a solder material of the solder film of theconductive mounting board 13, both solder materials can be desirablymelted without excessively increasing the heating temperature. Theheating is preferably performed in an atmosphere of a nitrogen gas (N₂)or hydrogen gas (H₂) or a mixed gas thereof for preventing oxidation ofthe solder materials. Also the semiconductor laser 20 may be pusheddown, for example, by applying a load thereon for preventing thepositions of the insulating mounting board 14 and the semiconductorlaser 20 from being deviated due to the surface tension of the soldermaterials.

A wire 17 is then laid out to connect the wiring portion 14 c of theinsulating mounting board 14 to the pin 15. After that, a cover body 12separately formed is disposed on the support 11 in an dried nitrogenatmosphere, thereby completing fabrication of the semiconductor lightemitting device and the package thereof as shown in FIG. 3.

The functions of the semiconductor light emitting device and the package10 thus obtained will be described below.

In the semiconductor light emitting device, when a specific voltage isapplied between the n-side electrode 28 a and the p-side electrode 28 bof the semiconductor laser 20 via the pins 15 and 18 of the package 10,a current is injected into the active layer 26 to cause light emissionby recombination of electrons with positive holes. The light isreciprocated between the pair of reflector films 29 to be amplified, andis emitted from one reflector film 29 as a laser beam. The laser beamthus emitted from the semiconductor laser 20 is extracted outwardly fromthe package 10 via the extraction window 12 a of the package 10.

At this time, in the semiconductor laser 20, heat generation occursmainly at the active layer 26. In this embodiment, since the conductivemounting board 13 is directly connected to the p-side electrode 28 b toshorten the distance between the active layer 26 and the conductivemounting board 13, heat generated in the active layer 26 is positivelyradiated via the conductive mounting board 13. As a result, thetemperature rise of the semiconductor laser 20 is suppressed, so thatthe semiconductor laser 20 can be stably operated for a long-period oftime.

Further, in this embodiment, since the insulating mounting board 14 isdisposed on the recessed portion 13 a of the conductive mounting board13 and the n-side electrode 28 a is electrically connected to the wiringportion 14 c of the insulating mounting board 14, the insulation betweenthe conductive mounting board 13 and the wiring portion 14 c is ensured,to thereby prevent short-circuit between the n-side electrode 28 a andthe p-side electrode 28 b.

In this way, according to the semiconductor light emitting device inthis embodiment, since the p-side electrode 28 b is directly connectedto the conductive mounting board 13, the distance between the activelayer 26 and the conductive mounting board 13 can be shortened, andconsequently, heat generated in the active layer 26 can be positivelyradiated via the conductive mounting board 13. As a result, it ispossible to suppress the temperature rise of the semiconductor laser 20and to stably operate the semiconductor laser 20 for a long-period oftime, and hence to improve the reliability of the semiconductor lightemitting device.

Also since the insulating mounting board 14 is disposed on the recessedportion 13 a of the conductive mounting board 13 and the n-sideelectrode 28 a is connected to the wiring portion 14 c of the insulatingmounting board 14, it is possible to ensure insulation between theconductive mounting board 13 and the wiring portion 14 c, and hence toprevent short-circuit between the n-side electrode 28 a and the p-sideelectrode 28 b of the semiconductor laser 20.

According to the package 10 in this embodiment, since the recessedportion 13 a and the projecting portion 13 b are formed on theconductive mounting board 13 and the insulating mounting board 14 isdisposed on the recessed portion 13 a, it is possible to preventshort-circuit between the n-side electrode 28 a and the p-side electrode28 b of the semiconductor laser 20 by disposing the n-side electrode 28a of the semiconductor laser 20 on the wiring portion provided on theinsulating mounting board 14 and disposing the p-side electrode 28 b onthe conductive mounting board 13. Also it is possible to positivelyradiate heat generated in the active layer 26 of the semiconductor laser20 via the conductive mounting board 13.

(Second Embodiment)

FIG. 7 shows a portion of a semiconductor light emitting device and aportion of a package according to a second embodiment of the presentinvention. The semiconductor light emitting device and the package inthis embodiment have the same configurations and the functions of thosein the first embodiment, except that a separating portion 33c isprovided on a conductive mounting board 33. And also they can befabricated in the same manner as that in the first embodiment. In thisembodiment, therefore, parts corresponding to those in the firstembodiment are designated by the same reference numerals as those in thefirst embodiment, and the detailed explanation thereof is omitted.

The separating portion 33 c is formed between a recessed portion 13 aand a projecting portion 13 b formed on the mounting surface of theconductive mounting board 33 in such a manner as to have a median heightbetween heights of the recessed portion 13 a and the projecting portion13 b. The separating portion 33 c is adapted to separate the conductivemounting board 33 from an insulating mounting board 14 with a gap kepttherebetween, thereby preventing short-circuit between the n-sideelectrode 28 a and the p-side electrode 28 b of the semiconductor laser20.

In this way, according to this embodiment, since the separating portion33 c is provided between the recessed portion 13 a and the projectingportion 13 b of the conductive mounting board 33, it is possible notonly to obtain the same effects as those obtained in the firstembodiment, but also to further effectively prevent short-circuitbetween the n-side electrode 28 a and the p-side electrode 28 b of thesemiconductor laser 20.

(Third Embodiment)

FIG. 8 shows a portion of a semiconductor light emitting device and aportion of a package according to a third embodiment of the presentinvention. The semiconductor light emitting device and the package inthis embodiment have the same configurations as those in the secondembodiment, except that a position fixing portion 43 d is provided on aconductive mounting board 43, having the same functions as those in thefirst embodiment and can be fabricated in the same manner as that in thefirst embodiment. Accordingly, parts corresponding to those in the firstand second embodiments are designated by the same reference numerals asthose in the first and second embodiments, and the detailed descriptionthereof is omitted.

The position fixing portion 43 d is formed on the mounting surface ofthe conductive mounting board 43 in such a manner as to provide arecessed portion 13 a between a projecting portion 13 b and the positionfixing portion 43 d. The position fixing portion 43 d projects upwardlyfrom the recessed portion 13 a, and holds an insulating mounting board14 between a separating portion 33 c and the position fixing portion 43d for preventing the position of the insulating mounting board 14 frombeing deviated upon soldering the insulating mounting board 14 to theconductive mounting board 13.

In this way, according to this embodiment, since the position fixingportion 43 d is provided on the conductive mounting board 33 in such amanner as to provide the recessed portion 13 a between the projectingportion 13 b and the position fixing portion 43 d, it is possible notonly to obtain the same effects as those obtained in the firstembodiment, but also to easily and accurately dispose the insulatingmounting board 14 on the conductive mounting board 43.

(Fourth Embodiment)

FIG. 9 shows a portion of a semiconductor light emitting device and aportion of a package according to a fourth embodiment of the presentinvention. The semiconductor light emitting device and the package inthis embodiment have the same configurations and the functions as thosein the first embodiment, except that the configurations of a conductivemounting board 53 and an insulating mounting board 54 are different fromthose in the first embodiment. Accordingly, parts corresponding to thosein the first embodiment are designated by the same reference numerals asthose in the first embodiment, and the detailed explanation thereof isomitted.

The conductive mounting board 53 is cast, integrally with a support 11,from a metal such as a copper or iron based metal. A thin film made froma metal such as gold or nickel (Ni) is formed on the surfaces of theconductive mounting board 53 and the support 11. Then, a solder adhesivelayer 53 e made from a solder material as described in the firstembodiment is provided on the surface of a projecting portion 13 b. Thesolder adhesive layer 53 e is adapted to adhesively bond a p-sideelectrode 28 b of a semiconductor laser 20 to the projecting portion 13b. The other configuration of the conductive mounting board 53 is thesame as that of the conductive mounting board 13 described in the firstembodiment.

The insulating mounting board 54 has an insulating board 54 a made fromsilicon dioxide being formed on a recessed portion 13 a of theconductive mounting board 53 by deposition. A wiring portion 54 c isprovided on the side, opposed to the conductive mounting board 53, ofthe insulating board 54 a. The wiring portion 54 c is formed by stackinga titanium layer having a thickness of 50 nm and a gold layer having athickness of 500 nm on the insulating board 54 a in this order. A solderadhesive layer 54 d made from the same solder material as that forforming the solder adhesive layer 53 e is provided on a portion of thewiring portion 54 c on the side opposed to the insulating board 54 a.The solder adhesive layer 54 d is adapted to adhesively bond an n-sideelectrode 28 a of the semiconductor laser 20 to the wiring portion 54 c.The solder material for forming the solder adhesive layer 54 d may bedifferent from that for forming the solder adhesive layer 53 e, however,the solder material is preferably the same as that for forming thesolder adhesive layer 53 e in order to form the solder adhesive layer 54d together with the solder adhesive layer 53 e at the same step in thefabrication method to be described later. The thickness of the solderadhesive layer 54 d is set at the same value as that of the solderadhesive layer 14 d in the first embodiment. The size of the insulatingmounting board 54 is set at the same value as that of the insulatingmounting board 14 in the first embodiment.

The semiconductor light emitting device and the package having the aboveconfigurations are fabricated in the following procedure:

First, a semiconductor laser 20 is formed in the same manner as that inthe first embodiment. Then, a support 11 and a conductive mounting board53 are integrally cast, and a thin film made from metal such as gold isformed on the surfaces of the support 11 and the conductive mountingboard 53 by plating.

The support 11 and the conductive mounting board 53 are cleaned, and asshown in FIG. 10, a mold 61 having an opening 61 a formedcorrespondingly to a recessed portion 13 a of the conductive mountingboard 53 is placed on the conductive mounting board 53 with the opening61 a aligned with the recessed portion 13 a. In this case, it may bedesirable that one side of the opening 61 a be positioned at theboundary between the recessed portion 13 a and a projecting portion 13 bof the conductive mounting board 53. After that, silicon dioxide isvapor-deposited from above onto the mold 61 at 200° C. by the electronbeam evaporation process, to form an insulating board 54 a on acrosshatched portion in FIG. 10. In addition, the size of the opening 61a of the mold 61 is preferably larger than that of the recessed portion13 a. The reason for this is that if the size of the opening 61 a issmaller than that of the recessed portion 13 a, the size of aninsulating mounting board 54 becomes smaller, thereby making itimpossible to prevent short-circuit between the n-side electrode 28 aand the p-side electrode 28 b of the semiconductor laser 20. Here, thewidth of the opening 61 a in the direction parallel to the support 11 isset at 0.8 mm, and the depth of the opening 61 a in the directionperpendicular to the support 11 is set at 1.1 mm.

After forming the insulating board 54 a, as shown in FIG. 11, a mold 62having an opening 62 a formed correspondingly to the insulatingsubstrate 54 a is placed on the conductive mounting board 53 with theopening 62 a aligned with the insulating board 54 a. Then, titanium,platinum and gold are sequentially vapor-deposited from above onto themold 62, to form a wiring portion 54 c on a crosshatched portion asshown in FIG. 11. In addition, the size of the opening 62 a ispreferably smaller than that of the opening 61 a of the mold 61 forpreventing short-circuit between the n-side electrode 28 a and thep-side electrode 28 b of the semiconductor laser 20. Here, the width ofthe opening 62 a is set at 0.7 mm and the depth thereof is set at 1.0mm. In other words, the opening 62 a of the mold 62 is positionedin-side of the opening 61 a of the mold 61.

After forming the wiring portion 54 c, as shown in FIG. 12, a mold 63having an opening 63 a formed correspondingly to the wiring portion 54 cand having an opening 63 b formed correspondingly to the projectingportion 13 b of the conductive mounting board 53 is placed on theconductive mounting board 53 in such a manner that the opening 63 a isaligned with the wiring portion 54 c and the opening 63 b is alignedwith the projecting portion 13 b. Then, a solder material isvapor-deposited from above onto the mold 63 by the vapor-depositionprocess, to form a solder adhesive layer 54 d and a solder adhesivelayer 53 e at crosshatched portions as shown in FIG. 12. In addition,the size of the opening 63 a is preferably smaller than that of theopening 61 a of the mold 61 for preventing short-circuit between then-side electrode 28 a and the p-side electrode 28 b of the semiconductorlaser 20. Here, the width of the opening 63 a is set at 0.35 mm and thedepth thereof is set at 1.0 mm. In other words, the opening 63 a of themold 63 is positioned in-side of the opening 61 a of the mold 61. Thesize of the opening 63 b is set such that the width is 0.80 mm and thedepth is 1.0 mm.

After forming the solder adhesive layers 53 e and 54 d, pins 15, 16 and18 separately formed are disposed to the support 11. Then, thesemiconductor layer 20 is disposed on the conductive mounting board 53and the insulating mounting board 54 in the same manner as thatdescribed in the first embodiment. After that, like the firstembodiment, a wire 17 is laid out to connect the wiring portion 54 c tothe pin 15 therebetween, and then a cover body 12 separately formed isdisposed on the support 11. In this way, the semiconductor lightemitting device and the package shown in FIG. 9 is obtained.

In this way, according co this embodiment, since the insulating mountingboard 54 is formed on the recessed portion 13 a of the conductivemounting board 53 by vapor-deposition, it is possible not only to obtainthe same effects as those obtained in the first embodiment, but also toeasily form the insulating mounting board 54 at a low cost.

(Fifth Embodiment)

FIG. 13 shows the entire configurations of a semiconductor lightemitting device and a package 70 according to a fifth embodiment of thepresent invention. The semiconductor light emitting device and thepackage 70 in this embodiment have the same configurations as thosedescribed in the first embodiment, except that the configuration of asemiconductor laser 80 is different from that in the first embodimentand correspondingly the configurations of a conductive mounting board 73and an insulating mounting board 74 are different from those in thefirst embodiment. In this embodiment, parts corresponding to those inthe first embodiment are designated by the same reference numerals asthose in the first embodiment, and the detailed description there of isomitted.

As enlargedly shown in FIG. 14, the semiconductor laser 80 has, on onesurface of the same substrate 81, a plurality (two in this embodiment)of light emitting portions 80 a and 80 b arranged in the directionperpendicular to the resonator orientation. It should be noted that theresonator is oriented in the direction perpendicular to the paper planein FIG. 14. The substrate 81, which has a thickness of about 100 μm, ismade from semi-insulating GaAs. The light emitting portions 80 a and 80b are formed on the (100) face of the substrate 81.

Each of the light emitting portions 80 a and 80 b having the samestructure is formed by sequentially stacking a buffer layer 82, ann-type semiconductor layer 83 as a first conduction type semiconductorlayer, an active layer 84, and a p-type semiconductor layer 85 as asecond conduction type semiconductor layer on the substrate 81 in thisorder. The buffer layer 82, which has a thickness of 50 nm, is made fromn-type GaAs doped with an n-type impurity such as silicon (Si) orselenium (Se), respectively.

The n-type semiconductor layer 83 is formed by stacking an n-type cladlayer 83 a and a first guide layer 83 b on the buffer layer 82 in thisorder. The n-type clad layer 83 a, which has a thickness of 1.0 μm, ismade from a mixed crystal, n-type Al_(0.40)Ga_(0.60)As doped with ann-type impurity such as silicon or selenium. The first guide layer 83 b,which has a thickness of 10 nm, is made from a mixed crystal, n-typeAl_(0.17)Ga_(0.83)As doped with an n-type impurity such as silicon orselenium, respectively.

The active layer 84, which is made from a mixed crystal, undoped AlGaAs,has a multiple quantum well structure composed of a well layer having athickness of 10 nm and made from Al_(0.07)Ga_(0.93)As and a barrierlayer having a thickness of 5 nm and made from Al_(0.17)Ga_(0.83)As. Theactive layer 84 in each of the light emitting portions 80 a and 80 bfunctions as a light emitting layer which emits light having awavelength of about 790 nm, respectively.

The p-type semiconductor layer 85 is formed by sequentially stacking asecond guide layer 85 a, a p-type clad layer 85 b and a cap layer 85 con the active layer 84 in this order. The second guide layer 85 a, whichhas a thickness of 10 nm, is made from a mixed crystal, p-typeAl_(0.17)Ga_(0.83)As doped with a p-type impurity such as zinc (Zn) Thep-type clad layer 85 b, which has a thickness of 1.0 μm, is made from amixed crystal, p-type Al_(0.40)Ga_(0.60)As doped with a p-type impuritysuch as zinc. The cap layer 85 c, which has a thickness of 50 nm, ismade from p-type GaAs doped with a p-type impurity such as zinc,respectively.

Current block layers 86 extending along the resonator orientation areinserted in both sides of a portion of the p-type clad layer 85 b in thestacking direction. To be more specific, the portion of the p-type cladlayer 85 b in the stacking direction has a narrow width in the directionperpendicular to the resonator orientation for the purpose of currentconstriction. Each current block layer 86, which has a thickness of 700nm, and is made from n-type GaAs doped with an n-type impurity such assilicon or selenium, respectively.

Each of the light emitting portions 80 a and 80 b has an n-sideelectrode 87 a as a first electrode on a portion, on the side where theactive layer 84 is provided in the stacking direction, of the n-typeclad layer 83 a. The n-side electrode 87 a is for me d by sequentiallystacking a gold-germanium (Ge) alloy layer, a nickel layer, and a goldlayer on the n-type clad layer 83 a in this order, and alloying thelayers by heating. The n-side electrode 87 a is electrically connectedto the n-type clad layer 83 a, respectively.

Each of the light emitting portions 80 a and 80 b has a p-side electrode87 b as a second electrode on a portion, on the side opposed to theactive layer 84 of the cap layer 85 c. The p-side electrode 87 b isformed by stacking a titanium layer, a platinum (Pt) layer, and a goldlayer on th e cap layer 85 c in this order, and alloying the layers byheating. The p-side electrode 87 b is electrically connected to the caplayer 85 c, respectively.

The reason why the n-side electrode 87 a and the p-side electrode 87 bare formed on the same side in the stacking direction is that thedistance between each electrode and the active layer 84 is shortened tomake the responsivity of each of the light emitting portions 80 a and 80b enhanced. Further, in the light emitting portions 80 a and 80 b, thetwo p-side electrodes 87 b are adjacent to each other, and the twon-side electrodes 87 a are disposed in such a manner as to provide thetwo p-side electrodes 87 b therebetween.

Each of the light emitting portions 80 a and 80 b has a pair ofreflector films 88 (only one is shown in FIG. 14) at end portions in theresonator orientation. One reflector film 88, having a low reflectance,is made from aluminum oxide (Al₂O₃). The other reflector film (notshown), having a high reflectance, is formed by alternately stackingaluminum oxide layers and amorphous silicon layers. Light generated fromthe active layer 84 is reciprocated between the pair of reflector films88 to be amplified, and is emitted from one reflector film 88 as a laserbeam.

As shown in FIG. 13, a conductive mounting board 73 of the package 70has on its mounting surface a pair of recessed portions 73 a and oneprojecting portion 73 b provided therebetween. The pair of recessedportions 73 a are formed correspondingly to the n-side electrodes 87 aof the semiconductor laser 80, and the projecting portion 73 b is formedcorrespondingly to the p-side electrodes 87 b of the semiconductor laser80. The size of each recessed portion 73 a is set such that the width is0.2 mm and the depth is 1 mm, and the size of the projecting portion 73b is set such that the width is 0.4 mm and the depth is 1 mm. Adifference in height between the mounting surfaces of the recessedportion 73 a and the projecting portion 73 b is 300 μm. The sizes ofeach of recessed portions 73 a may be different from each other,however, they are preferably identical to each other in order to reducethe number of kinds of insulating mounting boards 74 to be mounted onthe recessed portions 73 a, thereby improving the productivity. Theother configuration of the conductive mounting board 73 is the same asthat of the conductive mounting board 13 in the first embodiment.

The insulating mounting board 74 of the package 70 is disposed on eachof the pair of the recessed portions 73 a of the conductive mountingboard 73. While not shown, like the insulating mounting board 14 in thefirst embodiment, the insulating mounting board 74 has an insulatingboard made from an insulating material; an adhesive layer formed on thesurface, on the conductive mounting board 74 side, of the insulatingboard; a wiring portion formed on the surface, opposed to the conductivemounting board 73, of the insulating board; and a solder adhesive layerformed on a portion of the surface, opposed to the insulating board, ofthe wiring portion. The configuration of the insulating mounting board74 is the same as that of the insulating mounting board 14 in the firstembodiment. The size of the insulating mounting board 74 is set suchthat the width is 0.2 mm and the depth is 1 mm. The thickness of theinsulating mounting board 74 is the same as that of the insulatingmounting board 14 in the first embodiment.

The wiring portion of one insulating mounting board 74 is connected to apin 15 by means of a wire 17, and the wiring portion of the otherinsulating mounting board 74 is connected to a pin 16 by means of a wire77. The semiconductor laser 80 is disposed such that n-side electrodes87 a are in contact with the solder adhesive layers of the insulatingmounting boards 74 and the p-side electrodes 87 b are in contact withthe projecting portion 73 b of the conductive mounting board 73. That isto say, the n-side electrode 87 a of the light emitting portion 80 a isconnect e d to a power source (not shown) from the pin 16 by way of thewiring portion provided on the insulating mounting board 74 and the wire77, and the n-side electrode 87 a of the light emitting portion 80 b isconnected to a power source (not shown) from the pin 15 by way of thewiring portion provided on the insulating mounting board 74 and the wire17. On the other hand, the p-side electrodes 87 b of the light emittingportions 80 a and 80 b are connected to a power source (not shown) fromthe pin 18 by way of the conductive mounting board 73, respectively.

In this embodiment, since each p-side electrode 87 b including theactive layer 84 between the substrate 81 and the same is in contact withthe conductive mounting board 73 like the first embodiment, it ispossible to positively radiate heat generated in each active layer 84via the conductive mounting board 73.

The semiconductor light emitting device and the package 70 having theabove configurations are fabricated in the following procedure:

First, the semiconductor laser 80 is fabricated as follows: A substrate81 made from semi-insulating GaAs and having a plurality ofsemiconductor laser formation regions is prepared. A buffer layer 82made from n-type GaAs; an n-type clad layer 83 a made from a mixedcrystal, n-type Al_(0.40)Ga_(0.60)As; a first guide layer 83 b made froma mixed crystal, n-type Al_(0.17)Ga_(0.83)As; an active layer 84 madefrom a mixed crystal, undoped AlGaAs; a second guide layer 85 a madefrom a mixed crystal, p-type Al_(0.17)Ga_(0.83)As; and part of a p-typeclad layer 85 b made from a mixed crystal, p-type Al_(0.40)Ga_(0.60)Asare allowed to sequentially grow on one surface (100 face) of thesubstrate 81 by MOCVD.

A current block layer 86 made from n-type GaAs is allowed to selectivelygrow on the p-type clad layer 85 b by MOCVD. After selectively growingthe current block layer 86, the remainder of the p-type clad layer 85 bmade from a mixed crystal, p-type Al_(0.40)Ga_(0.60)As and a cap layer85 c made from p-type GaAs are allowed to sequentially grow on thecurrent block layer 86 and the p-type clad layer 85 b by MOCVD

After forming the layers up to the cap layer 85 c, the cap layer 85 c,the current block layer 86, the p-type clad layer 85 b, the second guidelayer 85 a, the active layer 84, the first guide layer 83 b, the n-typeclad layer 83 a, and the buffer layer 82 are selectively removed insequence correspondingly to formation positions of light emittingportions 80 a and 80 b by lithography, to separate the light emittingportions 80 a and 80 b from each other.

After separating the light emitting portions 80 a and 80 b from eachother, the cap layer 85 c, the current block layer 86, the p-type cladlayer 85 b, the second guide layer 85 a, the active layer 84, the firstguide layer 83 b, and part of the n-type clad layer 83 a are selectivelyremoved in sequence correspondingly to formation positions of n-sideelectrodes 87 a in the light emitting portions 80 a and 80 b bylithography, to expose the n-type clad layers 83 a in the light emittingportions 80 a and 80 b. Then, the n-side electrode 87 a is selectivelyformed on each n-type clad layer 83 a, and then a p-side electrode 87 bis selectively formed on each cap layer 85 c. After that, the n-sideelectrodes 87 a and the p-side electrodes 87 b in the light emittingportions 80 a and 80 b are each alloyed by heating.

After forming the n-side electrodes 87 a and the p-side electrodes 87 b,the substrate 81 is divided in the direction perpendicular to theresonator orientation into parts each having a specific lengthcorresponding to the length of each semiconductor laser formationregion. A pair of reflector films 88 are formed on a pair of sidesurfaces of the divided part by CVD. Then, the substrate 81 of each partis divided in the direction parallel to the resonator orientation intoparts each having a specific width corresponding to the width of eachsemiconductor laser formation region. In this way, the semiconductorlaser 80 is obtained.

Next, like the first embodiment, a support 11 and a conductive mountingboard 73 are integrally cast, and a solder film is vapor-deposited onthe surfaces of the support 11 and the conductive mounting board 73.Pins 15, 16 and 18 separately formed are disposed on the support 11.Subsequently, like the first embodiment, insulating mounting boards 74are separately formed.

After forming the insulating mounting boards 74, like the firstembodiment, the insulating mounting board 74 is mounted on a recessedportion 73 a of each conductive mounting board 73, and each p-sideelectrode 87 b of the semiconductor laser 80 is brought into contactwith a projecting portion 73 b of the conductive mounting board 73 andeach n-side electrode 87 a is brought into contact with a solderadhesive layer of each insulating mounting board 74. The assembly isheated by a heating apparatus (not shown), so that a solder film of theconductive mounting board 73 is melted to adhesively bond eachinsulating mounting board 74 to the conductive mounting board 73 and toadhesively bond each p-side electrode 87 b of the semiconductor laser 80to the conductive mounting board 73. Besides, the solder adhesive layerof each insulating mounting board 74 is melted to adhesively bond eachn-side electrode 87 a of the semiconductor laser 80 to each insulatingmounting board 74.

After that, a wire 17 is laid out to connect a wiring portion of oneinsulating mounting board 74 to the pin 15, and a wire 77 is laid out toconnect a wiring portion of the other insulating mounting board 74 tothe pin 16. After connecting the wires 17 and 77, like the firstembodiment, a cover body 12 separately formed is disposed to the support11. In this way, the semiconductor light emitting device and the package70 shown in FIG. 13 are formed.

The functions of the semiconductor light emitting device and the package70 thus formed will be described below.

In this semiconductor light emitting device, when a specific voltage isapplied to between each n-side electrode 87 a and the associated p-sideelectrode 87 b of the semiconductor laser 80 via the pins 15, 16 and 18of the package 70, a current is injected in the associated active layer84 of the semiconductor laser 80, to cause light emission byrecombination of electrons with positive holes. Light thus generated isreciprocated between the pair of reflector films 88 to be amplified, andis emitted from one reflector film 88 as a laser beam. The laser beamthus emitted from the semiconductor laser 80 is extracted outwardly fromthe package 70 via an extraction window 12 a of the package 70.

At this time, in the semiconductor laser 80, heat generation occursmainly at the active layer 84 of each of the light emitting portions 80a and 80 b. In this embodiment, since each p-side electrode 87 b isdirectly connected to the conductive mounting board 73 and thereby thedistance between each active layer 84 and the conductive mounting board73 is shortened, and thus heat generated in each active layer 84 ispositively radiated via the conductive mounting board 73. Accordingly,it is possible to suppress thermal interference between the lightemitting portions 80 a and 80 b of the semiconductor laser 80, and henceto suppress an increase in threshold current and also suppress areduction in luminous efficiency.

In this embodiment, since the insulating mounting board 74 is disposedon each recessed portion 73 a of the conductive mounting board 73 andeach n-side electrode 87 a is electrically connected to the wiringportion provided on the insulating mounting board 74, it is possible toensure electrical insulation between the conductive mounting board 73and the wiring portion, and hence to prevent short-circuit between then-side electrode 87 a and the p-side electrode 87 b. In addition, it ispossible to ensure electrical insulation between the wiring portionsprovided on both the insulating mounting board 74, and to ensureindependent drive of the light emitting portions 80 a and 80 b.

In this way, according to the semiconductor light emitting device inthis embodiment, since each p-side electrode 87 b is directly connectedto the conductive mounting board 73, the distance between each activelayer 84 and the conductive mounting board 73 can be shortened tothereby positively radiate heat generated in the active layer 84 via theconductive mounting board 73. As a result, it is possible to suppressthermal interference between the light emitting portions 80 a and 80 b.That is to say, it is possible to suppress an increase in thresholdcurrent and a reduction in luminous efficiency, and hence to maintain ahigh quality of the device for a long-period of time.

Also since the insulating mounting board 74 is disposed on each recessedportion 73 a of the conductive mounting board 73 and each n-sideelectrode 87 a is connected to the wiring portion provided on theinsulating mounting board 74, it is possible to ensure electricalinsulation between each wiring portion and the conductive mounting board73, and hence to prevent short-circuit between each n-side electrode 87a and the associated p-side electrode 87 b of the semiconductor laser80. Further, it is possible to ensure electrical insulation between thewiring portions for the light emitting portions 80 a and 80 b, and henceto ensure independent drive of the light emitting portions 80 a and 80b.

According to the package 70 in this embodiment, since the two recessedportions 73 a and the projecting portion 73 b are formed on theconductive mounting board 73, and the insulating mounting board 74 isdisposed on each recessed portion 73 a, it is possible to preventshort-circuit between each n-side electrode 87 a and the associatedp-side electrode 87 b of the semiconductor laser 80 by disposing then-side electrode 87 a on the wiring portion provided on the insulatingmounting board 74 and disposing the associated p-side electrode 87 b onthe conductive mounting board 73. Also it is possible to ensureelectrical insulation between both the n-side electrodes 87 a providedin the light emitting portions 80 a and 80 b and hence to ensureindependent drive of the light emitting portions 80 a and 80 b. Further,it is possible to positively radiate heat generated in each active layerof the semiconductor laser 80 via the conductive mounting board 13.

Although not described in detail, the semiconductor light emittingdevice in this embodiment may be configured such that the sameseparating portion as that in the second embodiment is provided on theconductive mounting board 73. Besides, the same position fixing portionas that in the third embodiment may be provided on the conductivemounting board 73; and the insulating mounting board 74 may be formed oneach recessed portion 73 a of the conductive mounting board 73 bydeposition, like the fourth embodiment.

(Sixth Embodiment)

FIG. 15 shows a portion of a semiconductor light emitting device and aportion of a package according to a sixth embodiment of the presentinvention. The semiconductor light emitting device and the package inthis embodiment have the same configurations and functions as those inthe fifth embodiment, except that a semiconductor laser 100 has three ormore light emitting portions 100 a and correspondingly, theconfigurations of a conductive mounting board 93 and an insulatingmounting board 94 are different from those in the fifth embodiment, andthey can be fabricated in the same manner as that described in the fifthembodiment. Accordingly, in this embodiment, parts corresponding tothose in the fifth embodiment are designated by the same referencenumerals as those in the fifth embodiment, and the detailed explanationthereof is omitted.

The semiconductor laser 100 has, in this embodiment, five light emittingportions 100 a each of which has the same configuration. In these lightemitting portions 100 a, n-side electrodes and p-side electrodes areformed so as to be alternately arranged. The other configuration of thesemiconductor laser 100 is the same as that of the semiconductor la ser80 in the fifth embodiment.

The conductive mounting board 93 has on its mounting surface fiveprojecting portions 93 b and recessed portions 93 a formed to surroundeach projecting portion 93 b in an U-shape. The recessed portions 93 aare formed correspondingly to the n-side electrodes of the semiconductorlaser 100, and the projecting portions 93 b are formed correspondinglyto the p-side electrodes of the semiconductor laser 100. The otherconfiguration of the conductive mounting board 93 is the same as that ofthe conductive mounting board 73 described in the fifth embodiment.

The insulating mounting board 94, which is disposed on the recessedportions 93 a of the conductive mounting board 93, has an insulatingboard 94 a made from an insulating material and formed into a comb-shapecorresponding to the recessed portions 93 a of the conductive mountingboard 93. An adhesive layer 94 b is formed all over the surface, on theconductive mounting board 94 side, of the insulating board 94 a. Wiringportions 94 c, which are independent from each other correspondinglyprovided to the n-side electrodes of the semiconductor laser 100, areformed on the surface, opposed to the conductive mounting board 93, ofthe insulating board 94 a. A solder adhesive layer 94 d is formed on aportion of the surface, opposed to the insulating board 94 a of eachwiring portion 94 c. The materials for forming the insulating board 94a, the adhesive layer 94 b, each wiring portion 94 d, and each solderadhesive layer 94 d are the same as those used in the fifth embodiment.The thickness of the insulating mounting board 94 is the same as that inthe fifth embodiment.

The semiconductor laser 100 is disposed such that each n-side electrodeis in contact with the associated solder adhesive layer 94 d of theinsulating mounting board 94 and each p-side electrode is in contactwith the associated projecting portion 73 b of the conductive mountingboard 73. While not shown, each wiring portion 94 c of the insulatingmounting board 94 is connected to different pins. That is to say,according to this embodiment, even the semiconductor laser having threeor more light emitting portions 100 a can exhibit the same effect asthat in the fifth embodiment.

While not described in detail, the semiconductor light emitting devicein this embodiment may be configured such that the same separatingportion as that in the second embodiment may be provided on theconductive mounting board 93; the same position fixing portion as thatin the third embodiment may be provided on the conductive mounting board93; and the insulating mounting board 94 may be formed on the recessedportion 93 a of the conductive mounting board 93 by deposition, like thefourth embodiment.

While the embodiments of the present invention have been described, thepresent invention is not limited thereto, and it is to be understoodthat various changes may be made with departing from the spirit or scopeof the present invention. For example, although each of the conductivemounting boards 13, 33, 43, 53, 73, 93 is made from the metal, it may bemade from a conductive material other than the metal.

In each of the first, second, third, fifth, and sixth embodiments, eachof the insulating mounting boards 14, 74 and 94 is made from theinsulating material such as aluminum nitride, boron nitride or siliconcarbide, however, it may be made from a different insulating materialsuch as silicon dioxide, silicon nitride (Si₃N₄), aluminum oxide(Al₂O₃), amorphous silicon, zirconium oxide (ZrO) or titanium oxide(TiO).

In the fourth embodiment, the insulating mounting board 54 is made fromsilicon dioxide, however, it may be made from a different insulatingmaterial such as aluminum nitride, boron nitride, silicon carbide,silicon nitride, alumninum oxide, amorphous silicon, zirconium oxide ortitanium oxide.

In each of the embodiments, the recessed portions 13 a, 73 a and 93 aand the projecting portions 13 b, 73 b and 93 b of the conductivemounting boards 13, 33, 43, 53, 73 and 93 are each flattened, however,as shown in FIGS. 16 and 17, recessed portions 113 a and 123 a andprojecting portions 113 b and 123 b of conductive mounting boards 113and 123 may be each configured to have one or more recesses and one ormore projections. However, each of a contact area between the conductivemounting board and the insulating mounting board and a contact areabetween the conductive mounting board and the semiconductor element maybe made large for increasing the heat radiation effect.

In each of the embodiment, the first conduction type semiconductor layeris taken as the n-type semiconductor layer 25 or 83 and the secondconduction type semiconductOr layer is taken as the p-type semiconductorlayer 27 or 85, however, the first conduction type semiconductor layermay be taken as a p-type semiconductor layer and the second conductiontype semiconductor layer be taken as an n-type semiconductor layer.However, in the case where the crystallinity of the n-type semiconductorlayer is superior to that of the p-type semiconductor layer, forexample, in the case of a compound semiconductor composed of a nitridecontaining nitrogen and a group III element, it may be desirable that ann-type semiconductor layer, an active layer, and a p-type semiconductorlayer sequentially grow on a substrate, in order to suitably obtain adesirable semiconductor light emitting element.

In each of the first to fourth embodiments, the compound semiconductorcomposed of the group III based nitride for forming each of the n-typesemiconductor layer 25, the active layer 26, the p-type semiconductorlayer 27, and the like of the semiconductor laser 20 is exemplarilydescribed, however, according to the present invention, it may bereplaced with a suitable compound semiconductor composed of a differentgroup III based nitride containing nitrogen (N) and at least one kind ofgroup III-element selected from the group consisting of gallium (Ga),aluminum (Al), boron (B) and indium (In).

Further, in each of the first to fourth embodiments, each of the n-typesemiconductor layer 25, the active layer 26, the p-type semiconductorlayer 27, and the like of the semiconductor laser 20 is made from thecompound semiconductor composed of the group III based nitride, however,according to the present invention, the above layer may be made from adifferent semiconductor. However, it should be noted that the presentinvention is particularly effective to a semiconductor light emittingdevice in which a semiconductor element is configured such that thefirst electrode and the second electrode are positioned on the same sidein the stacking direction, more specifically, in which the semiconductorelement has the first conduction type semiconductor layer, the activelayer, and the second conduction type semiconductor layer sequentiallystacked, and the first electrode is positioned on the side, on the sidewhere the active layer is provided, of the first conduction typesemiconductor layer and the second electrode is positioned on the side,opposed to the active layer, of the second conduction type semiconductorlayer.

In each of the fifth and sixth embodiments, the semiconductor forforming each of the n-type semiconductor layer 83, the active layer 84,the p-type semiconductor layer 85, and the like of each of the lightemitting portions 80 a, 80 b and 100 a is exemplarily described,however, according to the present invention, it may be replaced with adifferent semiconductor, for example, a group II-V compoundsemiconductor or a group II-VI compound semiconductor.

In each of the embodiments, the configuration of the semiconductor laseris exemplirily described, however, the present invention is not limitedthereto. For example, the semiconductor laser of the present inventionmay be configured such that the deterioration preventive layer 27 a maynot be provided; each of the first guide layer 25 c and 83 b and thesecond guide layer 27 b and 85 a may be made from a undopedsemiconductor; or the current constriction may be performed in a mannerdifferent from that described in the embodiments.

In each of the embodiments, the semiconductor device is configured as asemiconductor light emitting device including a semiconductor laser,however, the present invention is applicable to a semiconductor lightemitting device including a different semiconductor light emittingelement such as a light emitting diode, and also applicable to asemiconductor device including a semiconductor element other than thesemiconductor light emitting device.

Additionally, in each of the embodiments, each of the first conductiontype semiconductor layer, the active layer, the second conduction typesemiconductor layer, and the like of each of the semiconductor lasers20, 80 and 100 is formed by MOCVD, however, it may be formed by adifferent vapor-phase growth process such as a MBE process or a halidevapor-phase growth process, also called a hydride vapor-phase growthprocess, in which halogen contributes to transportation or reaction of araw material.

(Seventh Embodiment)

FIG. 18 shows the entire configuration of a semiconductor light emittingdevice as a semiconductor device according to one embodiment of thepresent invention. The semiconductor light emitting device includes asemiconductor laser 210 as a semiconductor element and a package 220 forcontaining the semiconductor laser 210.

FIG. 19 shows a partial cross-sectional structure of the semiconductorlaser 210. The semiconductor laser 210 is formed by sequentiallystacking a plurality of semiconductor layers on one surface of a pair ofopposed surfaces of a substrate 211, via a buffer layer 212 a, a backinglayer 212 b, a mask layer 213, and a coating growth layer 214. Theplurality of semiconductor layers are composed of an n-typesemiconductor layer 215 as a first conduction type semiconductor layer,an active layer 216, and a p-type semiconductor layer 217 as a secondconduction type semiconductor layer, which are stacked on the substrate211 in this order. The substrate 211 is formed of a sapphire having athickness in the stacking direction (hereinafter, referred to simply as“thickness”) of 300 μm, and the buffer layer 212 a is formed on theC-face of the substrate 211.

The buffer layer 212 a, which has a thickness of 30 nm, is made from anundoped GaN. The backing layer 212 b, which has a thickness of 2 μm, ismade from a crystal of undoped GaN. The mask layer 213, which has athickness of 0.1 μm, is made from silicon dioxide (SiO₂). The mask layer213 has a plurality of stripe-shaped openings 213 a extending in thedirection perpendicular to the paper plane in FIG. 19, and a pluralityof stripe-shaped mask portions 213 b each formed between adjacent two ofthe openings 213 a. The coating growth layer 214 grows laterally on themask layer 213, to thereby cutoff penetration of dislocations from thebacking layer 212 b. The coating growth layer 214, which has a thicknessof 10 μm, is made from undoped GaN.

The n-type semiconductor layer 215 is formed by stacking an n-sidecontact layer 215 a, an n-type clad layer 215 b, and a first guide layer215 c on the coating growth layer 214 in this order. The n-side contactlayer 215 a, which has a thickness of 3 μm, is made from n-type GaNdoped with an n-type impurity such as silicon (Si). The n-type cladlayer 215 b, which has a thickness of 1 μm, is made from a mixedcrystal, n-type Al_(0.1)Ga_(0.9)N doped with an n-type impurity such assilicon. The first guide layer 215 c, which has a thickness of 0.1 μm,is made from n-type GaN doped with an n-type impurity such as silicon.

The active layer 216 is made from a mixed crystal, undoped InGaN, andhas a multiple quantum well structure including a well layer having athickness of 3 nm and made from a mixed crystal, In_(0.15)Ga_(0.85)N,and a barrier layer having a thickness of 7 nm and made from a mixedcrystal, In_(0.02)Ga_(0.98)N. The active layer 216 functions as a lightemitting layer. For example, upon laser oscillation, the emissionwavelength is set at about 405 nm.

The p-type semiconductor layer 217 is formed by stacking a deteriorationpreventive layer 217 a, a second guide layer 217 b, a p-type clad layer217 c, and a p-side contact layer 217 d on the active layer 216 in thisorder. The deterioration preventive layer 217 a, which has a thicknessof 20 nm, is made from a mixed crystal, p-type Al_(0.2)Ga_(0.8)N dopedwith a p-type impurity such as magnesium (Mg). The second guide layer217 b, which has a thickness of 0.1 μm, is made from p-type GaN dopedwith a p-type impurity such as magnesium. The p-type clad layer 217 c,which has a thickness of 0.8 μm, is made from a mixed crystal, p-typeAl_(0.1)Ga_(0.9)N doped with a p-type impurity such as magnesium. Thep-side contact layer 217 d, which has a thickness of 0.1 μm, is madefrom a mixed crystal, p-type GaN doped with a p-type impurity such asmagnesium.

An n-side electrode 218 a as a first electrode is provided on thesurface, on the p-type semiconductor layer 217 side in the stackingdirection, of the n-side contact layer 215 a. An insulating layer 218 bmade from silicon dioxide is formed on the side, opposed to the n-typesemiconductor layer 215 in the stacking direction, of the p-side contactlayer 217 d, and a p-side electrode 218 c as a second electrode isprovided on the p-side contact layer 217 d through an opening formed inthe insulating layer 218 b. That is to say, in the semiconductor laser210, the n-side electrode 218 a and the p-side electrode 218 c areformed on the same side in the stacking direction.

The n-side electrode 218 a is formed by stacking a titanium (Ti) layer,an aluminum (Al) layer, a platinum (Pt) layer, and a gold (Au) layer onthe n-side contact layer 215 a in this order and alloying these metalsby heating, to be thus electrically connected to the n-side contactlayer 215 a. The p-side electrode 218 c is formed by stacking a nickel(Ni) layer, a platinum layer and a gold layer on the p-side contactlayer 217 d in this order and alloying these metals by heating, to bethus electrically connected to the p-side contact layer 217 d. Thep-side electrode 218 c is formed into a stripe shape extending in thedirection perpendicular to the paper plane in FIG. 19 for currentconstriction, and a region of the active layer 216 corresponding to thep-side electrode 218 c becomes a light emission region.

The semiconductor laser 210 has a pair of reflector films 219 (only oneis shown in FIG. 19) at both ends of the p-side electrode 218 c in thelength direction. Each reflector film 219 is formed by alternatelystacking silicon dioxide films and zirconium oxide (ZrO₂) films. Thereflectance of one reflector film 219 is set at a low value and thereflectance of the other reflector film (not shown) is set at a highvalue, so that light generated from the active layer 216 is reciprocatedbetween the pair of reflector films 219 to be amplified, and is emittedfrom one reflector film 219 as a laser beam. That is to say, the lengthdirection of the p-side electrode 218 c becomes the resonatororientation.

FIG. 20 is an exploded view of a portion of the package 220. The package220 includes a conductive mounting board 221 for supporting thesemiconductor laser 210 and radiating heat generated in thesemiconductor laser 210; and a support 222, formed into a circular ringshape, for supporting the conductive mounting board 221 by a supportingsurface 222 a.

The conductive mounting board 221 has a mounting surface 221 a on whichthe semiconductor laser 210 is to be disposed. The mounting surface 221a is perpendicular to the supporting surface 222 a. As shown in FIG. 18,of the n-side electrode 218 a and the p-side electrode 218 c of thesemiconductor laser 210, the p-side electrode 218 c (including theinsulating layer 218 b) is fixed on the mounting surface 221 a.Specifically, the conductive mounting board 221 supports thesemiconductor laser 210 in a state in which the n-side electrode 218 aprojects from the conductive mounting board 221 in the directionparallel to the mounting surface 221 a and the supporting surface 222 a.The reason why the p-side electrode 218 c is in contact with theconductive mounting board 221 is that the active layer 216 as a mainheat generation source is located between the p-side electrode 218 c andthe substrate 211. That is to say, by shortening the distance betweenthe active layer 216 and the conductive mounting board 221 having a highheat radiation effect, it is possible to effectively radiate heatgenerated in the active layer 216 via the conductive mounting board 221.

When the mounting surface 221 a of the conductive mounting board 221 islocated in such a manner as to extend in the horizontal direction, thatis, to be directed upwardly, the conductive mounting board 221 isshifted rightwardly, downwardly from the center of the supportingsurface 222 a of the support 222. The reason for this is that even ifthe semiconductor laser 210 is disposed on the conductive mounting board221 with the n-side electrode 218 a projecting therefrom, thesemiconductor laser 210 is located at the central portion of the support222. The conductive mounting board 221 has a side surface 221 b at anend portion, near the center of the support 222, in the directionparallel to the mounting surface 221 a and the supporting surface 222 a.That is to say, the conductive mounting board 221 has the side surface221 b on the side on which the n-side electrode 218 a of thesemiconductor laser 210 projects. The side surface 221 b is tilted, fromthe mounting surface 221 a side to the opposed side, toward the opposedend of the mounting surface 221 a, that is, toward the p-side electrode218 c side. The reason for this is to, as will be apparent in thedescription of the fabrication steps, easily connect a wire 227 to then-side electrode 218 a of the semiconductor laser 210.

As shown in FIG. 21, the end, on the side surface 221 b side, of themounting surface 221 a may be desired to project leftwardly from acenter perpendicular line I of the support 222 when the mounting surface221 a is directed upwardly, in order to locate the light emitting regionof the active layer 216 of the semiconductor laser 210 at the center ofthe support 222. Further, a width “w” between the end, on the sidesurface 221 b side, of the mounting surface 221 a and the end, opposedto the side surface 221 b, of the n-side electrode 218 a is limiteddepending on the size of a capillary (not shown) used for connection ofthe wire 227 in the fabrication steps to be described later. Here, thedistance “t” between the center perpendicular line I of the support 222and the end, on the side surface 221 b side, of the mounting surface 221a when the mounting surface 221 a is directed upwardly is set at about50 μm, and the above width “w” is set at about 300 μm.

As shown in FIG. 20, one of a pair of opposed side surfaces of thesupport 222 is taken as the support surface 222 a. The outer peripheralsurface of the support 222 has a plurality of fixing grooves 222 b, 22c, 22 d and 22 e. The fixing groove 222 b is adapted to fix theconductive mounting board 221 with the mounting surface 221 a directeddownwardly in the fabrication steps to be described later. The fixinggroove 222 c is adapted to fix the conductive mounting board 221 withthe mounting surface 221 a directed upwardly. The fixing grooves 222 dand 222 e are used for disposing the package 220.

The conductive mounting board 221 and the support 222 are integrallycast from a metal such copper (Cu), and a thin film made from nickel isformed on the surfaces of the conductive mounting board 221 and thesupport 222. A solder film (not shown) made from a solder material andhaving a thickness of 4 to 6 μm is formed on the mounting surface 221 aof the conductive mounting board 221. Specific examples of the soldermaterials may include tin (Sn), lead (Pb), a tin-lead alloy, a gold-tinalloy, an indium (In)-tin alloy, and an indium-lead alloy.

A disk member 223 is mounted on the inner peripheral surface of thesupport 222. A pin 224 is formed on one surface, opposed to theconductive mounting board 221, of a pair of side surfaces of the diskmember 223. The pin 224 is electrically connected to a power source (notshown) and is also electrically connected to the conductive mountingboard 221. Specifically, the p-side electrode 218 c of the semiconductorlaser 210 is electrically connected to the power source (not shown) bymeans of the pin 224 via the conductive mounting board 221. In addition,the disk member 223 and the pin 224 are integrally cast from a metalsuch as an iron (Fe) based metal. The reason why the disk member 223 isseparated from the support 222 is to facilitate the work of forming thesolder film on the mounting surface 221 a of the conductive mountingboard 221 and hence to improve the productivity.

A pair of pins 225 and 226 to be electrically connected to power sources(not shown) are provided on the disk member 223 in such a manner as topass through the disk member 223 from one side surface to the other sidesurface thereof. Each of the pins 225 and 226 is made from a metal suchas copper, on the surface of which a thin film made from gold is formed.Insulating rings 225 a and 226 a made from glass are inserted betweenthe disk member 223 and the pins 225 and 226, respectively, forelectrically insulating the disk member 223 from the pins 225 and 226.In other words, the conductive mounting board 221 is electricallyinsulated from the pins 225 and 226.

One end of a wire 227 made from gold and having a thickness of 30 μm isconnected to the pin 225, and the other end of the wire 227 is connectedto the n-side electrode 218 a of the semiconductor laser 210. That is tosay, the n-side electrode 218 a is electrically connected to the powersource (not shown) by means of the pin 225 via the wire 227.

As shown in FIG. 18, a hollowed cylinder shaped cover body 228 forcovering the semiconductor laser 210 and the conductive mounting board221 is mounted on the supporting surface 222 a of the support 222. Thecover body 228 is provided for preventing both contamination andoxidation due to atmospheric air of the semiconductor laser 210 and forpreventing whisker-like growth of solder on the mounting surface 221 aof the conductive mounting board 221. The cover body 228 is made from ametal such as a copper or iron based metal. One end portion of the coverbody 228 is opened and is in contact with the supporting surface 222 aof the support 222, and the other end portion of the cover body 228 isclosed and has an extraction window 228 a for extracting a laser beamemitted from the semiconductor laser 210 contained in the cover body 228outwardly from the package 220. The extraction window 228 a is made froma material allowing transmission of a laser beam emitted from thesemiconductor laser 210, for example, glass or plastic. In addition, areflection preventive film for preventing reflection of a laser beamemitted from the semiconductor laser 210 is preferably formed on theextraction window 228 a in order to prevent degradation of thecharacteristic thereof and occurrence of stray light.

The semiconductor device having the above configurations is fabricatedin accordance with the following procedure:

First, a semiconductor laser 210 is formed as follows: A substrate 211made from a sapphire having a plurality of semiconductor laser formationregions is prepared. A buffer layer 212 a made from undoped GaN and abacking layer 212 b made from undoped GaN are allowed to sequentiallygrow on one surface (C-face) of the substrate 211 by MOCVD (MetalOrganic Chemical Vapor Deposition). Then, a silicon dioxide layer isformed on the backing layer 212 b by an electron beam evaporationprocess and is patterned by lithography to selectively form a mask layer213 having a plurality of stripe-shaped mask portions 13 b. A coatinggrowth layer 214 made from undoped GaN is allowed to selectively grow inthe lateral direction from the openings 13 a on the mask layer 213 byMOCVD.

Then, an n-side contact layer 215 a made from n-type GaN, an n-type cladlayer 215 b made from n-type Al_(0.1)Ga_(0.9)N (mixed crystal), a firstguide layer 215 c made from n-type GaN, an active layer 216 made fromundoped GaInN (mixed crystal), a deterioration preventive layer 217 amade from p-type Al_(0.2)Ga_(0.8)N (mixed crystal), a second guide layer217 b made from p-type GaN, a p-type clad layer 217 c made from p-typeAl_(0.2)Ga_(0.9)N (mixed crystal), and a p-side contact layer 217 d madefrom p-type GaN are allowed to sequentially to grow on the coatinggrowth layer 214 by MOCVD.

After growth of the layers in the order from the n-side contact layer215 a to the p-side contact layer 17 d, it may be desirable to activatecarriers by heating in a nitrogen (N₂) atmosphere at a temperatureranging from 800 to 900° C. as needed. Then, an insulating layer 218 bmade from silicon dioxide is formed on the p-side contact layer 217 d byelectron beam evaporation. Next, the insulating layer 218 b, the p-sidecontact layer 217 d, the p-type clad layer 217 c, the second guide layer217 b, the deterioration preventive layer 217 a, the active layer 216,the first guide layer 215 c, and the n-type clad layer 215 b areselectively removed in sequence correspondingly to a formation positionof an n-side electrode 218 a by lithography and RIE (Reactive IonEtching), to expose the n-side contact layer 215 a.

After exposure of the n-side contact layer 215 a, the n-side electrode218 a is selectively formed on the n-side contact layer 215 a bylift-off and electron beam evaporation. After forming the n-side contactlayer 215 a, the insulating layer 218 b is selectively removedcorrespondingly to a formation position of a p-side electrode 218 c bylithography. Then, the p-side electrode 218 c is selectively formed onthe p-side contact layer 217 d by lift-off and electron beamevaporation. The n-side electrode 218 a and the p-side electrode 218 care each alloyed by heating.

After heat-treatment, lapping is made to make thin the thickness of thesubstrate 211. The substrate 211 is then divided, in the directionperpendicular to the length direction of the p-side electrode 218 c,into parts each having a specific length corresponding to that of eachsemiconductor laser formation region. A pair of reflector films 219 areformed on a pair of side surfaces of the divided part by electron beamevaporation. Then, the substrate 211 is divided, in the directionparallel to the length direction of the p-side electrode 218 c, intoparts having a specific width corresponding to that of eachsemiconductor laser formation region, to form a semiconductor laser 210.

After that, a conductive mounting board 221 and a support 222 areintegrally cast, and a thin film made from nickel is formed on thesurfaces of the conductive mounting board 221 and the support 222 byplating. Next, as shown in FIG. 22, the support 222 and the conductivemounting board 221 are inserted in a mounting hole 231 a of a holdingjig 231 with the mounting surface 221 a directed upwardly. In this case,the fixing groove 222 c of the support 222 is fitted around a fixingprojection 231 b of the holding jig 231, so that the support 222 and theconductive mounting board 221 are fixed on the holding jig 231. A mold232 having an opening 232 a corresponding to the mounting surface 221 ais placed on the conductive mounting board 221, and a solder film madefrom tin is vapor-deposited on the mounting surface 221 a by aresistance heating type vapor-deposition apparatus.

On the other hand, a disk member 223 and a pin 224 are integrally cast,and pins 225 and 226 are prepared. The pins 225 and 226 are mounted tothe disk member 223 via insulating rings 225 a and 226 a, respectively.As shown in FIG. 23, the disk member 223 thus prepared is mounted to thesupport 222. The semiconductor laser 210 is then disposed such that then-side electrode 218 a projects from the conductive mounting board 221in the direction parallel to the mounting surface 221 a and thesupporting surface 222 a and the p-side electrode 218 c and theinsulating layer 218 b are in contact with the mounting surface 221 a.That is to say, of the n-side electrode 218 a and the p-side electrode218 c, only the p-side electrode 218 c is, together with the insulatinglayer 218 b, brought into contact with the mounting surface 221 a.

The assembly thus prepared is then heated for 10 to 30 sec at atemperature of 235° C. or more to melt the solder film, whereby thep-side electrode 218 c and the insulating layer 218 b are fixed on theconductive mounting board 221 by soldering. The heating for soldering ispreferably performed in an atmosphere containing nitrogen gas, hydrogengas (H₂), or a mixed gas thereof for preventing oxidation of the soldermaterial. For example, in the case using tin as the solder material, itmay be desirable to use a mixed gas containing nitrogen gas and hydrogengas at a mixing ratio of N₂:H₂=16:1. Also it may be desirable to usuallykeep the flow state of the mixed gas. Further, the semiconductor laser210 is preferably pushed down, for example, by applying a load thereonfor preventing the positional offset of the semiconductor laser 210 dueto the surface tension of the molten solder material.

After the semiconductor laser 210 is mounted on the conductive mountingboard 221, as shown in FIG. 24, the support 222 is inserted in amounting hole 233 a of a holding jig 233 with the mounting surface 221 adirected downwardly. That is to say, the semiconductor laser 210 ispositioned on the lower side and the conductive mounting board 221 ispositioned on the upper side. At this time, the fixing groove 222 b ofthe support 222 is fitted around a fixing projection 233 b of theholding jig 233, so that the support 222 is fixed on the holding jig233. At this time, the substrate 211 side of the semiconductor laser 210is supported by an upper surface 233 c of the holding jig 233.

The support 211 is heated at 100° C., and the n-side electrode 218 a ofthe semiconductor laser 210 is connected to the pin 225 with a wire 227by using a capillary 234. In this embodiment, the side surface 221 b ofthe conductive mounting board 221 is tilted, from the mounting surface221 a side to the opposed side, toward the opposed end of the mountingsurface 221 a, and accordingly a space near the n-side electrode 218 ais broadened, so that the capillary 234 can be easily moved closer tothe n-side electrode 218 a. After connection of the wire 227, a coverbody 228 separately formed is mounted to the support 222 in a drynitrogen atmosphere. In this way, the semiconductor light emittingdevice shown in FIG. 18 is obtained.

The functions of the semiconductor light emitting device thus obtainedwill be described below.

In the semiconductor light emitting device, when a specific voltage isapplied between the n-side electrode 218 a and the p-side electrode 218c of the semiconductor laser 210 via the pins 225 and 224 of the package220, a current is injected in the active layer 216 to cause lightemission by recombination of electrons with positive holes. The light isreciprocated between the pair of reflector films 219 to be amplified,and is emitted from one reflector film 219 as a laser beam. The laserbeam thus emitted from the semiconductor laser 210 is extractedoutwardly from the package 220 via the extraction window 228 a of thepackage 220.

At this time, in the semiconductor laser 210, heat generation occursmainly at the active layer 216. In this embodiment, since the p-sideelectrode 218 c is directly connected to the conductive mounting board221 to shorten the distance between the active layer 216 and theconductive mounting board 221, heat generated in the active layer 216 ispositively radiated via the conductive mounting board 221. As a result,the temperature rise of the semiconductor laser 210 is suppressed, sothat the semiconductor laser 210 can stably operate for a long-period oftime.

Further, in this embodiment, since the p-side electrode 218 c of thesemiconductor laser 210 is fixed to the conductive mounting board 221and the n-side electrode 218 a of the semiconductor laser 210 projectsfrom the conductive mounting board 221, it is possible to preventshort-circuit between the n-side electrode 218 a and the p-sideelectrode 218 c.

In this way, according to the semiconductor light emitting device inthis embodiment, since the p-side electrode 218 c is fixed to theconductive mounting board 221 and the n-side electrode 218 a projectsfrom the conductive mounting board 221, it is possible to preventshort-circuit between the n-side electrode 218 a and the p-sideelectrode 218 c and to positively radiate heat generated in thesemiconductor laser 210 via the conductive mounting board 221.Accordingly, it is possible to suppress temperature rise of thesemiconductor laser 210 and keep a stable operational state of thedevice for a long-period of time, and hence to improve the reliabilityof the device.

In particular, since the p-side electrode 218 c is fixed to theconductive mounting board 221, it is possible to shorten the distancebetween the active layer 216 and the conductive mounting board 221, andhence to effectively radiate heat generated in the active layer 216.

Since the side surface 221 b of the conductive mounting board 221 istilted, from the mounting surface 221 a side to the opposed side, towardthe p-side electrode 218 c side, it is possible to broaden a space nearthe n-side electrode 218 a and hence to facilitate the connection of thewire to the n-side electrode 218 a. This makes it possible to facilitatethe electrical connection of the n-side electrode 218 a to a powersource.

Since the conductive mounting board 221 is located in such a manner asto be shifted rightwardly from the center of the supporting surface 222a with the mounting surface 221 a directed upwardly, it is possible toeasily fix the p-side electrode 218 c to the conductive mounting board221 in the slate in which the n-side electrode 218 a projects from theconductive mounting board 221 in the direction parallel to the mountingsurface 221 a and the supporting surface 222 a, and to locate thesemiconductor laser 210 at the central portion of the support 222.

Since the support 222 has the fixing groove 222 b for fixing theconductive mounting board 221 with the mounting surface 221 a directeddownwardly, it is possible to fix the n-side electrode 218 a and the pin225 on the holding jig 233 upon connection of the wire 227 between then-side electrode 218 a and the pin 225. Accordingly, it is possible tofacilitate the work for connecting the wire 227 and hence to facilitatethe electrical connection of the n-side electrode 218 a to a powersource.

According to the method of fabricating a semiconductor light emittingdevice in this embodiment, since the semiconductor laser 210 is formedand then the p-side electrode 218 c is fixed to the conductive mountingboard 221 in the state in which the n-side electrode 218 a projects fromthe conductive mounting board 221, it is possible to easily fabricatethe semiconductor light emitting device in this embodiment. Further,since the semiconductor laser 210 is located on the lower side and theconductive mounting board 221 is located on the upper side and in such astate the n-side electrode 218 a is connected to the pin 224 by means ofthe wire 227, it is possible to facilitate the connection of the wire227, and hence to facilitate the electrical connection of the n-sideelectrode 218 a to a power source.

To confirm the heat radiation effect of the semiconductor light emittingdevice in this embodiment, the following comparative experiment wasperformed. First, a semiconductor light emitting device according tothis embodiment shown in FIG. 18 was prepared, and a semiconductor lightemitting device shown in FIG. 25 was prepared as a comparative example.In this comparative example, the same semiconductor laser 210 as thatdescribed in this embodiment was mounted on a conductive mounting board2221 via a sub-mount 2229 made from aluminum nitride (AlN). A p-sideelectrode 218 c was connected to a wiring portion 2229 a disposed on thesub-mount 2229 and the wiring portion 2229 a was connected to theconductive mounting board 2221 via a wire 2227 a. An n-side electrode218 a was connected to a wiring portion 2229 b disposed on the sub-mount2229 and the wiring portion 2229 b was connected to a pin 2225 via awire 2227 b.

Each semiconductor light emitting device was put in a thermostat (notshown) kept at a temperature 20° C. and driven. In this drive state, thetemperature changes of the semiconductor lasers 210 and the conductivemounting boards 221 and 2221 were observed. In addition, a directcurrent of 300 mA was allowed to flow in each semiconductor laser 210.At this time, the operational voltage of each semiconductor laser 210was about 8 V. The temperature was measured by using thermocouplesattached to the substrate 211 and the conductive mounting board 221 (or2221) of each semiconductor laser 210.

As a result, it was revealed that the temperature of each semiconductorlight emitting device became stable after an elapse of about 10 secsince application of the voltage. In the semiconductor light emittingdevice in this embodiment, the temperature of the semiconductor laser210 was 30° C. and the temperature of the conductive mounting board 221was 24° C. That is to say, the temperature of the semiconductor laser210 was raised by 10° C. and the temperature of the conductive mountingboard 221 was raised by 4° C. On the contrary, in the semiconductorlight emitting device in the comparative example, the temperature of thesemiconductor laser 210 was 35° C. and the temperature of the conductivemounting board 2221 was 25° C. That is to say, the temperature of thesemiconductor laser 210 was raised by 15° C. and the temperature of theconductive mounting board 2221 was raised by 5° C. As a result, it wasrevealed that the semiconductor light emitting device in this embodimentexhibited a high heat radiation effect capable of effectivelysuppressing temperature rise of the semiconductor laser 210.

While the embodiment of the present invention has been described, thepresent invention is not limited thereto, and it is to be understoodthat various changes may be made with departing from the spirit or scopeof the present invention. For example, although the entire side surface221 b of the conductive mounting board 221 is tilted in the embodiment,only a portion of the side surface 221 b may be tilted.

In the embodiment, the conductive mounting board 221 is located in sucha manner as to be shifted rightwardly from the center of the supportingsurface 222 a when the mounting surface 221 a is directed upwardly,however, it may be located in such a manner as to be shifted leftwardly.That is to say, the conductive mounting board 221 may be shiftedrightwardly or leftwardly so that one of the n-side electrode 218 a andthe p-side electrode 218 c can be fixed thereto. However, in the casewhere the n-side electrode 218 a or the p-side electrode 218 c isconnected to the pin 225 in accordance with Japanese IndustrialStandards, it may be desirable to shift the conductive mounting board221 on the right side opposed to the pin 225 for facilitating theconnection of the wire between the electrode and the pin 225.

In the embodiment, the conductive mounting board 221 is made from ametal, however, it may be made from a conductive material other than ametal.

In the embodiment, the p-side electrode 218 c is fixed to the conductivemounting board 221 and the n-side electrode 218 a projects from theconductive mounting board 221, however, the n-side electrode 218 a maybe fixed to the conductive mounting board 221 and the p-side electrodemay project from the conductive mounting board 221.

In the embodiment, the first conduction type semiconductor layer istaken as the n-type semiconductor layer 215 and the second conductiontype semiconductor layer is taken as the p-type semiconductor layer 217,however, the first conduction type semiconductor layer may be taken as ap-type semiconductor layer and the second conduction type semiconductorlayer may be taken as an n-type semiconductor layer. However, in thecase where the crystallinity of the n-type semiconductor layer issuperior to that of the p-type semiconductor layer, for example, in thecase of a compound semiconductor composed of a nitride containingnitrogen and a group III element, it may be desirable that an n-typesemiconductor layer, an active layer, and a p-type semiconductor layersequentially grow on a substrate, in order to obtain a desirablesemiconductor light emitting element.

In the embodiment, the compound semiconductor composed of the group IIIbased nitride for forming each of the n-type semiconductor layer 215,the active layer 216, the p-type semiconductor layer 217, and the likeof the semiconductor laser 210 is exemplarily described, however,according to the present invention, it may be replaced with a suitablecompound semiconductor composed of a different group III based nitridecontaining nitrogen (N) and at least one kind of group III elementselected from the group consisting of gallium (Ga), aluminum (Al), boron(B) and indium (In).

Further, in the embodiment, each of the n-type semiconductor layer 215,the active layer 216, the p-type semiconductor layer 217, and the likeof the semiconductor laser 210 is made from the compound semiconductorcomposed of the group III based nitride, however, according to thepresent invention, the above layer may be made from a differentsemiconductor. However, it should be noted that as described in theembodiment, the present invention is particularly effective to asemiconductor light emitting device in which a semiconductor element isconfigured such that the first electrode and the second electrode arepositioned on the same side in the stacking direction.

In the embodiment, the configuration of the semiconductor laser 210 isexemplarily described, however, the present invention is not limitedthereto. For example, the semiconductor laser of the present inventionmay be configured such that the deterioration preventive layer 217 a isnot provided; each of the first guide layer 215 c and the second guidelayer 217 b is made from an undoped semiconductor; or the currentconstriction is performed in a manner different from that described inthe embodiment.

In the embodiment, the semiconductor device is configured as asemiconductor light emitting device including a semiconductor laser 210,however, the present invention is applicable to a semiconductor lightemitting device including a different semiconductor light emittingelement such as a light emitting diode, and also applicable to asemiconductor device including a semiconductor element other than thesemiconductor light emitting device.

Additionally, in the embodiment, each of the first conduction typesemiconductor layer 215, the active layer 216, the second conductiontype semiconductor layer 217, and the like of the semiconductor laser210 is formed by MOCVD, however, it may be formed by a differentvapor-phase growth process such as an MBE process or a halidevapor-phase growth process, also called a hydride vapor-phase growthprocess, in which halogen contributes to transportation or reaction of araw material.

What is claimed is:
 1. A method of fabricating a semiconductor device,comprising the steps of: forming a conductive mounting board having onits one surface a recessed portion and a projecting portion; forming aninsulating mounting board disposed on the recessed portion of saidconductive mounting board; forming a semiconductor element; anddisposing one portion of said semiconductor element on the projectingportion of the conductive mounting board and also disposing the otherportion of said semiconductor element on said insulating mounting board.2. A method of fabricating a semiconductor device according to claim 1,wherein said step of forming the semiconductor element comprises thestep of sequentially stacking a first conduction type semiconductorlayer, an active layer, and a second conduction type semiconductor layeron a substrate; and providing a first electrode on a portion, on theside where said active layer is provided, of said first conduction typesemiconductor layer and providing a second electrode on a portion, onsaid side opposed to said active layer, of said second conduction typesemiconductor layer, to thereby form said semiconductor element; andsaid step of disposing the semiconductor element comprises the steps ofdisposing said second electrode on said conductive mounting board anddisposing said first electrode on said insulating mounting board.
 3. Amethod of fabricating a semiconductor device according to claim 2,wherein said first conduction type semiconductor layer is formed of ann-type semiconductor layer, and said second conduction typesemiconductor layer is formed of a p-type semiconductor layer.
 4. Amethod of fabricating a semiconductor device according to claim 2,wherein each of said first conduction type semiconductor layer, saidactive layer, and said second conduction type semiconductor layer ismade from a compound semiconductor composed of a nitride containingnitrogen (N) and at least one kind of group III elements selected from agroup consisting of gallium (Ga), aluminum (Al), boron (B) and indium(In).
 5. A method of fabricating a semiconductor device according toclaim 1, wherein said step of forming the semiconductor elementcomprises the steps of forming a plurality of light emitting portions,each having a first conduction type semiconductor layer, an activelayer, and a second conduction type semiconductor layer, which aresequentially stacked on the same substrate, and providing a firstelectrode on a portion, on the side where said active layer is provided,of said first conduction type semiconductor layer and providing a secondelectrode on a portion, on the side opposed to said active layer, ofsaid second conduction type semiconductor layer, to thereby form saidsemiconductor element; and said step of disposing said semiconductorelement comprises the step of disposing said second electrode on saidconductive mounting board and disposing said first electrode on saidinsulating mounting board.
 6. A method of fabricating a semiconductordevice according to claim 1, further comprising the step of forming aseparating portion, between the recessed portion and the projectingportion of said conductive mounting board, for separating saidinsulating mounting board from said conductive mounting board with a gapkept therebetween.
 7. A method of fabricating a semiconductor deviceaccording to claim 1, further comprising the step of forming aprojecting position fixing portion for preventing the positional offsetof said insulating mounting board, on one surface of said conductivemounting board in such a manner as to provide the recessed portionbetween the projecting portion and said position fixing portion.
 8. Amethod of fabricating a semiconductor device according to claim 1,wherein said step of forming the insulating mounting board comprises thestep of forming said insulating mounting board on the recessed portionof said conductive mounting board by deposition.
 9. A method offabricating a package comprising the steps of: forming a conductivemounting board having on its one surface a recessed portion and aprojecting portion; and forming an insulating mounting board disposed onthe recessed portion of said conductive mounting board.
 10. A method offabricating a package according to claim 9, further comprising the stepof forming, between the recessed portion and the projecting portion ofsaid conductive mounting board, a separating portion for separating saidinsulating mounting board from said conductive mounting board with a gapkept therebetween.
 11. A method of fabricating a package comprising thestep of: forming a conductive mounting board having on its one surface arecessed portion on which an insulating mounting board is to be disposedand a projecting portion on which a semiconductor element is to bedisposed.
 12. A method of fabricating a package according to claim 11,further comprising the step of forming, between the recessed portion andthe projecting portion of said conductive mounting board, a separatingportion for separating said insulating mounting board disposed on therecessed portion from said conductive mounting board with a gap kepttherebetween.
 13. A method of fabricating a semiconductor device,comprising the steps of: stacking a plurality of semiconductor layerswhile providing a first electrode and a second electrode on the sameside in the stacking direction, to form a semiconductor element; anddisposing said semiconductor element on a conductive mounting boardwhile fixing either said first electrode or said second electrode onsaid conductive mounting board.
 14. A method of fabricating asemiconductor device according to claim 13, wherein said step of formingthe semiconductor element comprises the steps of: sequentially stackinga first conduction type semiconductor layer, an active layer, and asecond conduction type semiconductor layer; and providing a firstelectrode on a portion, on the side where said second conduction typesemiconductor layer is provided, of said first conduction typesemiconductor layer, and providing a second electrode on a portion, onthe side opposed to said first conduction type semiconductor layer, ofsaid second conduction type semiconductor layer.
 15. A method offabricating a semiconductor device according to claim 14, wherein saidfirst conduction type semiconductor layer is an n-type semiconductorlayer, and said second conduction type semiconductor layer is a p-typesemiconductor layer.
 16. A method of fabricating a semiconductor deviceaccording to claim 14, wherein each of said first conduction typesemiconductor layer, said active layer, and said second conduction typesemiconductor layer is made from a compound semiconductor composed of anitride containing nitrogen (N) and at least one kind of group IIIelement selected from a group consisting of gallium (Ga), aluminum (Al),boron (B) and indium (In).
 17. A method of fabricating a semiconductordevice according to claim 13, further comprising the steps of: fixingeither said first electrode or said second electrode of saidsemiconductor element to said mounting surface of said conductivemounting board; and allowing the other electrode to project from saidconductive mounting board in the direction parallel to said mountingsurface.
 18. A method of fabricating a semiconductor device according toclaim 13, further comprising the steps of: setting said conductivemounting board on which said semiconductor element has been mounted, insuch a manner that said semiconductor element is located on the lowerside and said conductive mounting board is located on the upper side;and connecting the other of said first electrode and said secondelectrode by means of a wire to a pin electrically insulated from saidconductive mounting board.